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    代码模板

    临时文件
      #include <bits/stdc++.h>
    #define debug(a) cout<<#a<<"="<<a<<"\n";
    #define rep(i,a,b) for(long long i=a;i<=b;i++)
    #define pep(i,a,b) for(long long i=a;i>=b;i--)
    using namespace std;
    long long maxx(long long x,long long y)
    {
    	return x>y?x:y;
    }
    long long minn(long long x,long long y)
    {
    	return x<y?x:y;
    }
    pair<long long,long long> mapp(long long x,long long y)
    {
    	return (pair<long long,long long>) {x,y};
    }
    long long n;
    long long op;
    long long k;
    long long addr_;
    string s;
    string ti;
    string ni;
    string c_in1[300];
    string c_in2[300];
    struct type_kind
    {
    	string name;
    	vector<type_kind*> son_type;
    	vector<string> son_name;
    	long long memo_size;
    	long long memo_align;
    	void clear()
    	{
    		name.clear();
    		son_type.clear();
    		son_name.clear();
    		memo_align=memo_size=0;
    	}
    };
    type_kind y_n_type[300];
    long long type_num;
    map<string,type_kind*> name_to_type;
    struct element
    {
    	type_kind element_type;
    	string name;
    	long long address;
    	void clear()
    	{
    		element_type.clear();
    		name.clear();
    		address=0;
    	}
    };
    element y_n_elem[300];
    long long ele_num;
    map<string,element*> name_to_ele;
    long long addr_pos;
    map<pair<long long,long long>,element*> addr_to_ele;
    void int_struct(string type_name,long long num,string *ar1,string *ar2)//操作1,定义结构体
    {
    	type_kind new_type;
    	new_type.clear();
    	new_type.name=type_name;
    	rep(i,1,num)
    	{
    		new_type.son_type.push_back(name_to_type[ar1[i]]);
    		new_type.son_name.push_back(ar2[i]);
    	}
    	long long pos=0;
    	vector<type_kind*>::iterator it=new_type.son_type.begin();
    	for(;it!=new_type.son_type.end();it++)
    	{
    		long long align=(*it)->memo_align;
    		long long size=(*it)->memo_size;
    		new_type.memo_align=max(new_type.memo_align,align);
    		if(pos%align)
    		{
    			pos=(pos/align+1)*align;
    		}
    		pos+=size;
    	}
    	if(pos%new_type.memo_align)
    	{
    		pos=(pos/new_type.memo_align+1)*new_type.memo_align;
    	}
    	new_type.memo_size=pos;
    	y_n_type[++type_num]=new_type;
    	name_to_type[type_name]=&y_n_type[type_num];
    }
    void int_element(string type_name,string ele_name)//操作2,定义元素
    {
    	element new_ele;
    	new_ele.clear();
    	long long align=name_to_type[type_name]->memo_align;
    	long long size=name_to_type[type_name]->memo_size;
    	if(addr_pos%align)
    	{
    		addr_pos=((addr_pos/align+1)*align);
    	}
    	new_ele.address=addr_pos;
    	new_ele.element_type=*name_to_type[type_name];
    	new_ele.name=ele_name;
    	y_n_elem[++ele_num]=new_ele;
    	name_to_ele[ele_name]=&y_n_elem[ele_num];
    	addr_to_ele[mapp(addr_pos,addr_pos+size-1)]=&y_n_elem[ele_num];
    	addr_pos+=size;
    }
    long long ask_element(string ele_name)//操作3,访问元素
    {
    	queue<string> name;
    	string tool;
    	tool.clear();
    	rep(i,0,(long long)ele_name.length()-1)
    	{
    		if(ele_name[i]=='.')
    		{
    			name.push(tool);
    			tool.clear();
    		}
    		else
    		{
    			tool+=ele_name[i];
    		}
    	}
    	name.push(tool);
    	long long pos=name_to_ele[name.front()]->address;
    	type_kind type=name_to_ele[name.front()]->element_type;
    	name.pop();
    	while(!name.empty())
    	{
    		string Name=name.front();
    		name.pop();
    		vector<string>::iterator it1=type.son_name.begin();
    		vector<type_kind*>::iterator it2=type.son_type.begin();
    		for(;it1!=type.son_name.end();it1++,it2++)
    		{
    			if(pos%(*it2)->memo_align)
    			{
    				pos=(pos/(*it2)->memo_align+1)*(*it2)->memo_align;
    			}
    			if(*it1==Name)
    			{
    				type=**it2;
    				break;
    			}
    			else
    			{
    				pos+=(*it2)->memo_size;
    			}
    		}
    	}
    	return pos;
    }
    string ask_addr(long long addr)//操作4,访问地址
    {
    	if(addr>=addr_pos)
    	{
    		return "ERR";
    	}
    	element ele;
    	map<pair<long long,long long>,element*>::iterator it=addr_to_ele.begin();
    	for(;it!=addr_to_ele.end();it++)
    	{
    		if(addr<(*it).first.first or addr>(*it).first.second)
    		{
    			continue;
    		}
    		ele=*((*it).second);
    		break;
    	}
    	long long pos_goal=addr-ele.address;
    	long long pos_s=0;
    	long long pos_t;
    	type_kind type=ele.element_type;
    	string ele_name;
    	ele_name.clear();
    	ele_name+=ele.name;
    	while(!type.son_name.empty())
    	{
    		vector<type_kind*>::iterator it1=type.son_type.begin();
    		vector<string>::iterator it2=type.son_name.begin();
    		for(;it1!=type.son_type.end();it1++,it2++)
    		{
    			pos_t=pos_s+(*it1)->memo_size;
    			if(pos_goal<pos_t&&pos_goal>=pos_s)
    			{
    				ele_name+='.'+*it2;
    				type=**it1;
    				break;
    			}
    			else
    			{
    				if(it1+1==type.son_type.end())
    				{
    					return "ERR";
    				}
    				long long align=(*(it1+1))->memo_align;
    				if(pos_t%align)
    				{
    					pos_t=(pos_t/align+1)*align;
    				}
    				if(pos_goal<pos_t)
    				{
    					return "ERR";
    				}
    				pos_s=pos_t;
    			}
    		}
    	}
    	if(ele_name=="")
    	{
    		return "ERR";
    	}
    	return ele_name;
    }
    int main()
    {
    	y_n_type[1].name="byte";
    	y_n_type[2].name="short";
    	y_n_type[3].name="int";
    	y_n_type[4].name="long";
    	y_n_type[1].memo_align=y_n_type[1].memo_size=1;
    	y_n_type[2].memo_align=y_n_type[2].memo_size=2;
    	y_n_type[3].memo_align=y_n_type[3].memo_size=4;
    	y_n_type[4].memo_align=y_n_type[4].memo_size=8;
    	name_to_type["byte"]=&y_n_type[1];
    	name_to_type["short"]=&y_n_type[2];
    	name_to_type["int"]=&y_n_type[3];
    	name_to_type["long"]=&y_n_type[4];
    	type_num=4;
    	cin>>n;
    	while(n--)
    	{
    		cin>>op;
    		if(op==1)
    		{
    			cin>>s>>k;
    			rep(i,1,k) cin>>c_in1[i]>>c_in2[i];
    			int_struct(s,k,c_in1,c_in2);
    			cout<<y_n_type[type_num].memo_size<<" "<<y_n_type[type_num].memo_align<<endl;
    		}
    		else if(op==2)
    		{
    			cin>>ti>>ni;
    			int_element(ti,ni);
    			cout<<y_n_elem[ele_num].address<<endl;
    		}
    		else if(op==3)
    		{
    			cin>>s;
    			cout<<ask_element(s)<<endl;
    		}
    		else if(op==4)
    		{
    			cin>>addr_;
    			cout<<ask_addr(addr_)<<endl;
    		}
    	}
    	return 0;
    }
    
    
    三分模板([ABC279D] Freefall)
    #include<bits/stdc++.h>
    #define int long long
    using namespace std;
    const double M=1e-10;
    int T,n;
    double a,b,ans;
    double f(double x){
    	return b*(x-1.0)+a/sqrt(x);
    }
    signed main(){
    		cin>>a>>b;
    		int l=0,r=1e18;
    		while(r-l>2){
    			int len=(r-l)/3;
    			int midl=l+len;
    			int midr=r-len;
    			if(f(midl)>f(midr)) l=midl;
    			else r=midr;
    		}
    	ans=min(f(l),min(f(r),f(l+1)));
    printf("%.10lf",ans);
    	return 0;
    }
    
    小秦种树(线段树)
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    const int N=4*2e5+50;
    int n,m,p[N],mx[N],mn[N],amx=-1e9,amn=1e9,sum[N],ans=0,xg[N];
    void build(int id,int l,int r){
    	if(l==r){
    		sum[id]=p[l];
    		if(sum[id]<=1)
    			xg[id]=1;
    		else
    			xg[id]=0;
    		return;
    	}
    	int mid=(l+r)/2;
    	build(id*2,l,mid);
    	build(id*2+1,mid+1,r);
    	xg[id]=xg[id*2]&xg[id*2+1];
    	sum[id]=sum[id*2]+sum[id*2+1];
    	return;
    }
    void find(int id,int l,int r,int x,int y){
    	if(x<=l&&r<=y){
    		ans+=sum[id];
    		return;
    	}
    	int mid=(l+r)/2;
    	if(mid>=x)
    		find(id*2,l,mid,x,y);
    	if(mid<y)
    		find(id*2+1,mid+1,r,x,y);
    	return;
    }
    void change(int id,int l,int r,int fl,int fr){
    	if(xg[id]==1)
    		return;
    	if(l==r){
    		sum[id]=sqrt(sum[id]);
    		if(sum[id]<=1)
    			xg[id]=1;
    		else
    			xg[id]=0;
    		return;
    	}
    	int mid=(l+r)/2;
    	if(mid>=fl)
    		change(id*2,l,mid,fl,fr);
    	if(mid<fr)
    		change(id*2+1,mid+1,r,fl,fr);
    		xg[id]=xg[id*2]&xg[id*2+1];
    	sum[id]=sum[id*2]+sum[id*2+1];
    	return;
    }
    signed main(){
    	ios::sync_with_stdio(0);
    	cin.tie(0);
    	cout.tie(0);
    	cin>>n;
    	for(int i=1;i<=n;i++)
    		cin>>p[i];
    	build(1,1,n);
    	cin>>m;
    	while(m--){
    		int k,a,b;
    		cin>>k>>a>>b;
    		if(k==1){
    			ans=0;
    			find(1,1,n,a,b);
    			cout<<ans<<"\n";
    		}else{
    				change(1,1,n,a,b);
    		}
    	}
    	return 0;
    }
    
    线段树单点修改区间查询
    #include <bits/stdc++.h>
    using namespace std;
    const int N=4*1e5+50;
    int n,m,p[N],mx[N],mn[N],amx=-1e9,amn=1e9,sum[N],ans=0;
    void build(int id,int l,int r){
    	if(l==r){
    		sum[id]=p[l];
    		return;
    	}
    	int mid=(l+r)/2;
    	build(id*2,l,mid);
    	build(id*2+1,mid+1,r);
    	sum[id]=sum[id*2]+sum[id*2+1];
    	return;
    }
    void find(int id,int l,int r,int x,int y){
    	if(x<=l&&r<=y){
    		ans+=sum[id];
    		return;
    	}
    	int mid=(l+r)/2;
    	if(mid>=x)
    		find(id*2,l,mid,x,y);
    	if(mid<y)
    		find(id*2+1,mid+1,r,x,y);
    	return;
    }
    void change(int id,int l,int r,int pos,int v){
    	if(l==r){
    		sum[id]+=v;
    		return;
    	}
    	int mid=(l+r)/2;
    	if(pos<=mid)
    		change(id*2,l,mid,pos,v);
    	else
    		change(id*2+1,mid+1,r,pos,v);
    	sum[id]=sum[id*2]+sum[id*2+1];
    }
    signed main(){
    	cin>>n>>m;
    	while(m--){
    		int k,a,b;
    		cin>>k>>a>>b;
    		if(k==0){
    			change(1,1,n,a,b);
    		}else{
    			ans=0;
    			find(1,1,n,a,b);
    			cout<<ans<<"\n";
    		}
    	}
    	return 0;
    }
    
    跳石头(二分答案)
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    int q,n,m,a[50050],l=1,r=1e9,mid,ans;
    bool check(int x){
    	int sum=0,last=0;
    	for(int i=1;i<=n+1;i++)
    		if(a[i]-last<x) sum++;
    		else last=a[i];
    		return sum<=m;
    }
    signed main(){
    	cin>>q>>n>>m;
    	for(int i=1;i<=n;i++)
    		cin>>a[i];
    	a[n+1]=q;
    	r=q;
    	while(l<=r){
    		mid=l+(r-l)/2;
    		if(check(mid)){
    			ans=mid;
    			l=mid+1;
    		}else r=mid-1;
    	}
    	cout<<ans;
    	return 0;
    }
    
    分解质因数
    #include <bits/stdc++.h>
    using namespace std;
    int n;
    signed main(){
    	cin>>n;
    	for(int i=2;i<=n;i++){
    		while(n%i==0){
    			cout<<i<<"\n";
    			n/=i;
    		}
    	}
    	return 0;
    }
    
    代码优化

    输入输出流关闭

    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    

    编译设置

    -std=c++11 -O2 -Wl,--stack=123456789
    
    对拍
    @echo off		
    :ss			
    Random.exe						
    My.exe			
    Std.exe		
    fc  My.out Std.out		
    if not errorlevel 1 goto ss 
    pause
    
    #include<bits/stdc++.h> 
    using namespace std;
    signed main()
    {
    	srand(time(0)); 
    	exit(0);
    }
    
    最小生成树(Prim)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=5005;
    int n,m,w[N][N],d[N],bs;
    bool vis[N];
    void prim(){
    	memset(d,0x3f,sizeof(d));
    	d[1]=0;
    	for(int i=1;i<=n;i++){
    		int k=0;
    		for(int j=1;j<=n;j++)
    			if(!vis[j]&&d[j]<d[k])
    				k=j;
    		vis[k]=1;
    		for(int j=1;j<=n;j++){
    			if(vis[j]==0&&w[k][j]<d[j]){
    				d[j]=w[k][j];
    			}
    		}
    	}
    }
    signed main(){
    	cin>>n>>m;
    	memset(w,0x3f,sizeof(w));
    	for(int i=1;i<=m;i++){
    		int x,y,z;
    		cin>>x>>y>>z;
    		if(w[x][y]>z)w[x][y]=w[y][x]=z;
    	}
    	prim();
    	int ans=0,flag=1;
    	for(int i=1;i<=n;i++){
    		if(d[i]==0x3f3f3f3f)
    			flag=0;
    		ans+=d[i];
    	}
    	if(flag==1)cout<<ans;
    	else cout<<"orz";
    	return 0;
    }
    
    ycz的离散化(离散化模板)
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    const int N=5000050;
    int n,k,a[N],p;
    signed main(){
    	cin>>n>>k;
    	for(int i=1;i<=n;i++)
    		cin>>a[i];
    	p=a[k];
    	sort(a+1,a+n+1);
    	int m=unique(a+1,a+n+1)-a;
    	cout<<lower_bound(a+1,a+m+1,p)-a;
    	return 0;
    }
    
    树状数组求逆序对
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    const int N=5100000;
    int n,m,b[N],ans,c[N],id[N];
    struct node{
    	int b,id;
    }a[N];
    int lowbit(int x){
    	return x&(-x);
    }
    long long sum(int x){
    	long long res=0;
    	for(int i=x;i;i-=lowbit(i))
    		res+=c[i];
    	return res;
    }
    void add(int x,int y){
    	for(int i=x;i<=1e7;i+=lowbit(i))
    		c[i]+=y;
    }
    bool cmp(node a,node b){
    	if(a.b!=b.b) return a.b>b.b;
    	else return a.id>b.id;
    }
    signed main(){
    	scanf("%lld",&m);
    	for(int i=1;i<=m;i++)
    		cin>>a[i].b,a[i].id=i;
    	sort(a+1,a+m+1,cmp);
    	for(int i=1;i<=m;i++){
    		ans+=sum(a[i].id);
    		add(a[i].id,1);
    	}
    	cout<<ans;
    	return 0;
    }
    
    
    
    
    并查集
    #include <bits/stdc++.h>
    #define MAXN 5010
    int n,m,p,x,y,fa[MAXN];
    int find(int x){
    	if(x==fa[x]) return x;
    	return fa[x]=find(fa[x]);
    }
    void join(int c1,int c2){
    	int f1=find(c1),f2=find(c2);
    	if(f1!=f2) fa[f1]=f2;
    }
    using namespace std;
    int main(){
    	cin>>n>>m;
    	for(int i=1;i<=n;i++) fa[i]=i;
    	for(int i=0;i<m;i++){
    		cin>>x>>y;
    		join(x,y);
    	}
    	cin>>p;
    	for(int i=0;i<p;i++){
    		cin>>x>>y;
    		if(find(x)==find(y)) cout<<"Yes"<<"\n";
    		else cout<<"No"<<"\n";
    	}
    	return 0;
    }
    
    01背包
    #include <bits/stdc++.h>
    using namespace std;
    const int N=305,M=20050;
    int v,n,a[N],f[M],ans,b[N];
    signed main(){
    	cin>>v>>n;
    	for(int i=1;i<=n;i++)
    		cin>>a[i]>>b[i];
    	f[0]=0;
    	for(int i=1;i<=n;i++)
    		for(int j=v;j>=a[i];j--){
    		f[j]=max(f[j],f[j-a[i]]+b[i]);	
    	}
    	for(int i=0;i<=v;i++)
    		ans=max(ans,f[i]);
    	cout<<ans;
    	return 0;
    }
    
    完全背包
    #include <bits/stdc++.h>
    using namespace std;
    const int N=305,M=20050;
    int v,n,a[N],f[M],ans,b[N];
    signed main(){
    	cin>>v>>n;
    	for(int i=1;i<=n;i++)
    		cin>>a[i]>>b[i];
    	f[0]=0;
    	for(int i=1;i<=n;i++)
    		for(int j=a[i];j<=v;j++){
    		f[j]=max(f[j],f[j-a[i]]+b[i]);	
    	}
    	for(int i=0;i<=v;i++)
    		ans=max(ans,f[i]);
    	cout<<ans;
    	return 0;
    }
    
    多重背包(二进制拆分)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=3500,M=200500;
    int v,n,a[N],f[M],ans,s[N],c,k[N];
    signed main(){
    	cin>>n>>v;
    	for(int i=1;i<=n;i++)
    		cin>>a[i];
    	for(int i=1;i<=n;i++)
    		cin>>s[i];
    	for(int i=1;i<=n;i++){
    		int o=s[i],t=1;
    		while(o>=t){
    			k[++c]=t*a[i];
    			o-=t;
    			t*=2;
    		}
    		k[++c]=a[i]*o;
    	}
    	f[0]=1;
    	for(int i=1;i<=c;i++)
    		for(int j=v;j>=0;j--)
    			if(f[j]==1){
    		f[j]=1;
    		if(k[i]+j<=v){
    			f[k[i]+j]=1;
    			
    		}				
    	}
    	for(int i=1;i<=v;i++)
    		if(f[i])
    			ans++;
    	cout<<ans;
    	return 0;
    }
    
    石子合并之二(合并类Dp)(断环成链)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=505;
    int n,a[N],sum[N],f[N][N];
    signed main(){
    	cin>>n;
    	for(int i=1;i<=n;i++)
    		cin>>a[i],a[i+n]=a[i];
    	for(int i=1;i<=2*n;i++)
    		sum[i]=sum[i-1]+a[i],f[i][i]=0;
    	for(int len=2;len<=2*n;len++){
    		for(int i=1;i<=2*n-len+1;i++){
    			int j=i+len-1;
    			f[i][j]=0x3f3f3f3f;
    			for(int mid=i;mid<=j-1;mid++){
    				f[i][j]=min(f[i][j],f[i][mid]+f[mid+1][j]+sum[j]-sum[i-1]);
    			}
    		}
    	}
    	int ans=INT_MAX;
    	for(int i=1;i<=n;i++)
    		ans=min(ans,f[i][i+n-1]);
    	cout<<ans;
    	return 0;
    }
    
    石子合并(合并类Dp)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=205;
    int n,a[N],sum[N],f[N][N];
    signed main(){
    	cin>>n;
    	for(int i=1;i<=n;i++)
    		cin>>a[i],sum[i]=sum[i-1]+a[i],f[i][i]=0;
    	for(int i=1;i<=n-1;i++)
    		f[i][i+1]=a[i]+a[i+1];
    	for(int len=3;len<=n;len++){
    		for(int i=1;i<=n-len+1;i++){
    			int j=i+len-1;
    			f[i][j]=0x3f3f3f3f;
    			for(int mid=i;mid<=j-1;mid++){
    				f[i][j]=min(f[i][j],f[i][mid]+f[mid+1][j]+sum[j]-sum[i-1]);
    			}
    		}
    	}
    	cout<<f[1][n]<<"\n";
    	return 0;
    }
    
    数字三角形
    #include <bits/stdc++.h>
    using namespace std;
    const int N=1005;
    int n,f[N][N],a[N][N];
    signed main(){
    	cin>>n;
    	for(int i=1;i<=n;i++)
    		for(int j=1;j<=i;j++)
    			cin>>a[i][j];
    	for(int i=1;i<=n;i++)
    		f[i][1]=a[i][1]+f[i-1][1];
    	for(int i=2;i<=n;i++)
    		for(int j=2;j<=i;j++){
    		f[i][j]=max(f[i-1][j-1],f[i-1][j])+a[i][j];
    		//		else if(i-1>=1)f[i][j]=f[i-1][j]+a[i][j];
    	}
    	int ans=0;
    	for(int i=1;i<=n;i++)
    		ans=max(ans,f[n][i]);
    	cout<<ans;
    	return 0;
    }
    
    最长上升子序列(加强版)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=40005;
    int n,a[N],f[N],ans,T;
    signed main(){
    	cin>>T;
    	while(T--){
    		ans=0;
    	cin>>n;
    	for(int i=1;i<=n;i++){
    		cin>>a[i];
    		f[i]=0;
    	}
    	for(int i=1;i<=n;i++){
    		if(i==1){
    			++ans;
    			f[ans]=a[i];
    		}else if(a[i]>f[ans]){
    			++ans;
    			f[ans]=a[i];
    		}else{
    			int s=a[i];
    			int g=lower_bound(f+1,f+ans+1,s)-f;
    			f[g]=a[i];
    		}
    	}
    	cout<<ans<<"\n";
    	}
    	return 0;
    }
    
    最长上升子序列
    #include <bits/stdc++.h>
    using namespace std;
    const int N=1005;
    int n,a[N],f[N],ans;
    signed main(){
    	cin>>n;
    	for(int i=1;i<=n;i++){
    		cin>>a[i];
    		f[i]=1;
    	}
    	for(int i=1;i<=n;i++){
    		for(int j=1;j<i;j++){
    			if(a[j]<a[i])
    				f[i]=max(f[i],f[j]+1);
    		}
    		ans=max(ans,f[i]);
    	}
    	cout<<ans<<"\n";
    	return 0;
    }
    
    售货员的难题(状压DP)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=25;
    int n,d[N][N];
    int f[N][400005];
    signed main(){
    	cin>>n;
    	memset(f,63,sizeof(f));
    	f[1][1]=0;
    	for(int i=1;i<=n;i++)
    		for(int j=1;j<=n;j++)
    			cin>>d[i][j];
    	for(int i=0;i<=(1<<n);i++){
    		for(int j=1;j<=n;j++){
    			if((i&(1<<j-1))==0){
    				for(int k=1;k<=n;k++){
    					if(i&(1<<k-1)){
    						f[j][(1<<j-1)|i]=min(f[j][(1<<j-1)|i],f[k][i]+d[k][j]);
    					}
    				}
    			}
    		}
    	}
    	int ans=INT_MAX;
    	for(int i=2;i<=n;i++)
    		ans=min(ans,f[i][(1<<n)-1]+d[i][1]);
    	cout<<ans<<"\n";
    	return 0;
    }
    
    最短路(Floyd)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=1005;
    int n,t,m,u[N],o;
    int w[N][N],ans=INT_MAX,d[N];
    void f(){
    	for(int k=1;k<=n;k++)
    		for(int i=1;i<=n;i++)
    			for(int j=1;j<=n;j++){
    			w[i][j]=min(w[i][j],max(w[i][k],w[k][j]));
    	}
    }
    signed main(){
    	int T;
    	cin>>n>>m>>T;
    	for(int i=1;i<=n;i++)
    		for(int j=1;j<=n;j++)
    			w[i][j]=1e9;
    	for(int i=1;i<=n;i++) w[i][i]=0;
    	for(int i=1;i<=m;i++){
    		int x,y,l;
    		cin>>x>>y>>l;
    		w[x][y]=l;
    //		w[y][x]=l;
    	}
    	f();
    	while(T--){
    		int s,t;
    		cin>>s>>t;
    		if(w[s][t]!=1e9)cout<<w[s][t]<<"\n";
    		else cout<<-1<<"\n";
    	}
    	return 0;
    }
    
    扩展欧几里得
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    int a,b,x,y,gcd,c;
    int exgcd(int a,int b,int &x,int &y){
    	if(b==0){
    		x=c/a,y=0;
    		return a;
    	}
    	int d=exgcd(b,a%b,x,y);
    	int tx=x;
    	x=y;
    	y=tx-(a/b)*y;
    	return d;
    }
    signed main(){
    	cin>>a>>b>>c;
    	int gcd=exgcd(a,b,x,y);
    	x=(x%b+b)%b;
    	b=b/gcd;
    	cout<<x<<"\n";
    	for(int i=1;i<gcd;i++)
    		cout<<x+i*b<<"\n";
    	return 0;
    }
    
    乘法逆元
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    int n,p,inv[3000050],mod=1e9+7,a,b;
    int c(int a,int b){
    	int ans=1;
    	for(int i=1;i<=b;i++)
    		ans=ans*(a-b+i)%mod*inv[i]%mod;
    	return ans;
    }
    int fpow(int ds,int zs,int modsss){
    	int sumsumsum=1;
    	while(zs){
    		if(zs&1)sumsumsum = (sumsumsum*ds)%modsss;
    		ds = (ds*ds)%modsss;
    		zs>>=1;
    	}
    	return sumsumsum;
    }
    signed main(){
    	cin>>n>>a>>b;
    	inv[1]=1;
    	p=mod;
    	for(int i=2;i<=max(a,b);i++)
    		inv[i]=(p-p/i)*inv[p%i]%p;
    	cout<<(fpow(2,n,mod)-c(n,a)-c(n,b)+3*mod-1)%mod;
    	return 0;
    }
    
    树状数组 3 :区间修改,区间查询
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    long long c[2][100005];
    int a[100005],n,m;
    int lowbit(int x){
    	return x&(-x);
    }
    long long sum(int x,int op){
    	long long res=0;
    	for(int i=x;i;i-=lowbit(i))
    		res+=c[op][i];
    	return res;
    }
    void add(int x,int y,int op){
    	for(int i=x;i<=n;i+=lowbit(i))
    		c[op][i]+=y;
    }
    signed main(){
    	scanf("%lld%lld",&n,&m);
    	for(int i=1;i<=n;i++){
    		scanf("%lld",&a[i]);
    		add(i,a[i],0);
    		add(i+1,-a[i],0);
    		add(i,1ll*(n-i+1)*a[i],1);
    		add(i+1,-1ll*(n-i)*a[i],1);
    	}
    	while(m--){
    		int x,y,d;
    		char op;
    		cin>>op;
    		scanf("%lld%lld",&x,&y);
    		if(op=='C'){
    			scanf("%lld",&d);
    			add(x,d,0);
    			add(y+1,-d,0);
    			add(x,(n-x+1)*d,1);
    			add(y+1,-(n-y)*d,1);
    		}else{
    			long long ans=sum(y,1)-1ll*(n-y)*sum(y,0);
    			ans-=sum(x-1,1)-1ll*(n-x+1)*sum(x-1,0);
    			printf("%lld\n",ans);
    		}
    	}
    	return 0;
    }
    
    树状数组 2 :区间修改,单点查询
    #include <bits/stdc++.h>
    using namespace std;
    const int N=5100000;
    int n,m,a[N],b[N];
    long long c[N];
    int lowbit(int x){
    	return x&(-x);
    }
    long long sum(int x){
    	long long res=0;
    	for(int i=x;i;i-=lowbit(i))
    		res+=c[i];
    	return res;
    }
    void add(int x,int y){
    	for(int i=x;i<=n;i+=lowbit(i))
    		c[i]+=y;
    }
    signed main(){
    	scanf("%d%d",&n,&m);
    	for(int i=1;i<=n;i++){
    		scanf("%d",&a[i]);
    		b[i]=a[i]-a[i-1];
    		add(i,b[i]);
    	}
    	while(m--){
    		int op,x,y,k;
    		scanf("%d",&op);
    		if(op==1){ 
    			scanf("%d%d%d",&x,&y,&k);
    			add(x,k);
    			add(y+1,-k);
    		}
    		else{ 
    			scanf("%d",&x);
    			printf("%lld\n",sum(x));
    		}
    	}
    	return 0;
    }
    
    树状数组 1 :单点修改,区间查询
    #include <bits/stdc++.h>
    #define int long long
    using namespace std;
    const int N=5100000;
    int n,m,a[N],c[N];
    int lowbit(int x){
    	return x&(-x);
    }
    int sum(int x){
    	long res=0;
    	for(int i=x;i;i-=lowbit(i))
    		res+=c[i];
    	return res;
    }
    void add(int x,int y){
    	for(int i=x;i<=n;i+=lowbit(i))
    		c[i]+=y;
    }
    signed main(){
    	scanf("%lld%lld",&n,&m);
    	for(int i=1;i<=n;i++){
    		scanf("%lld",&a[i]);
    		add(i,a[i]);
    	}
    	while(m--){
    		int op,x,y;
    		cin>>op>>x>>y;
    		if(op==1) add(x,y);
    		else printf("%lld\n",sum(y)-sum(x-1));
    	}
    	return 0;
    }
    
    RMQ
    #include<bits/stdc++.h>
    using namespace std;
    int n,q;
    int s[20],mx[50050][20],mn[50050][20];
    void pre(){
    	int x=log2(n);
    	for(int i=1;i<=x;i++)
    		for(int j=1;j+s[i]-1<=n;j++){
    			mx[j][i]=max(mx[j][i-1],mx[j+s[i-1]][i-1]);
    			mn[j][i]=min(mn[j][i-1],mn[j+s[i-1]][i-1]);
    		}
    }
    int rmq(int a,int b){
    	int x=log2(b-a+1);
    	int t1=max(mx[a][x],mx[b-s[x]+1][x]);
    	int t2=min(mn[a][x],mn[b-s[x]+1][x]);
    	return t1-t2;
    }
    signed main(){
    	cin>>n>>q;
    	s[0]=1;
    	for(int i=1;i<=15;i++)
    		s[i]=s[i-1]*2;
    	for(int i=1;i<=n;i++){
    		cin>>mx[i][0];
    		mn[i][0]=mx[i][0];
    	}
    	pre();
    	while(q--){
    		int x,y;
    		cin>>x>>y;
    		cout<<rmq(x,y)<<"\n";
    	}
    	return 0;
    }
    
    最近公共祖先(LCA)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=1000050;
    int n,q,d[N],f[N][105],s[105];
    vector<int> v[N];
    void dfs(int x,int fa,int dep){
    	d[x]=dep;
    	for(int i=0;i<v[x].size();i++){
    		int y=v[x][i];
    		if(y==fa) continue;
    		f[y][0]=x;
    		dfs(y,x,dep+1);
    	}
    }
    int lca(int x,int y){
    	if(d[y]<d[x]) swap(x,y);
    	int k=log2(d[y])+1;
    	for(int i=k;i>=0;i--)
    		if(d[y]-s[i]>=d[x])
    			y=f[y][i];
    	if(x==y) return x;
    	for(int i=k;i>=0;i--)
    		if(f[x][i]!=f[y][i]){
    			x=f[x][i];
    			y=f[y][i];
    		}
    	return f[x][0];
    }
    void pre(){
    	for(int j=1;s[j]<=n;j++)
    		for(int i=1;i<=n;i++)
    			f[i][j]=f[f[i][j-1]][j-1];
    }
    signed main(){
    	scanf("%d%d",&n,&q);
    	s[0]=1;
    	for(int i=1;i<=20;i++)
    		s[i]=s[i-1]*2;
    	for(int i=1;i<n;i++){
    		int x,y;
    		scanf("%d%d",&x,&y);
    		v[x].push_back(y);
    		v[y].push_back(x);
    	}
    	dfs(1,0,1);
    	pre();
    	while(q--){
    		int x,y;
    		scanf("%d%d",&x,&y);
    		printf("%d\n",lca(x,y));
    	}
    	return 0;
    }
    
    树的重心
    #include <bits/stdc++.h>
    using namespace std;
    const int N=20050;
    int n,f[N],g[N],h;
    vector<int> v[N];
    bool vis[N];
    void dfs(int x){
    	vis[x]=1;
    	f[x]=1;
    	g[x]=0;
    	for(int i=0;i<v[x].size();i++){
    		int y=v[x][i];
    		if(vis[y]) continue;
    		dfs(y);
    		f[x]+=f[y];
    		g[x]=max(g[x],f[y]);
    	}
    	g[x]=max(g[x],n-f[x]);
    }
    signed main(){
    	cin>>n;
    	for(int i=1;i<n;i++){
    		int x,y;
    		cin>>x>>y;
    		v[x].push_back(y);
    		v[y].push_back(x);
    	}
    	dfs(1);
    	int ans=INT_MAX;
    	for(int i=1;i<=n;i++)
    		ans=min(ans,g[i]);
    	for(int i=1;i<=n;i++)
    		if(g[i]==ans)
    			h=1,cout<<i<<"\n";
    	if(h==0)
    		cout<<"NONE"<<"\n";
    	return 0;
    }
    
    
    树的直径
    #include <bits/stdc++.h>
    using namespace std;
    const int N=200050;
    int n,s,ans,zz,res;
    struct node{
    	int v,w;
    };
    vector<node> v[N];
    void dfs(int x,int fa,int sum){
    	if(sum>ans)
    		ans=sum,zz=x;
    	for(int i=0;i<v[x].size();i++){
    		node y=v[x][i];
    		if(y.v==fa) continue;
    		dfs(y.v,x,sum+y.w);
    	}
    }
    signed main(){
    	cin>>n>>s;
    	for(int i=1;i<n;i++){
    		int x,y,w;
    		cin>>x>>y>>w;
    		v[x].push_back({y,w});
    		v[y].push_back({x,w});
    		res+=w;
    	}
    	dfs(s,0,0);
    	ans=0;
    	dfs(zz,0,0);
    	cout<<2*res-ans;
    	return 0;
    }
    
    最小生成树(Kruskal)
    #include <bits/stdc++.h>
    using namespace std;
    const int N=200050;
    int n,m,c[N],fa[N],ans,sw=INT_MAX;
    struct node{
    	int x,y,w;
    }a[N];
    bool cmp(node a,node b){
    	return a.w<b.w;
    }
    int find(int x){
    	if(x==fa[x]) return x;
    	else return fa[x]=find(fa[x]);
    }
    void add(int x,int y){
    	int p=find(x),q=find(y);
    	if(p!=q)
    		fa[p]=q;
    }
    void kru(){
    	sort(a+1,a+m+1,cmp);
    	for(int i=1;i<=n;i++)
    		fa[i]=i;
    	for(int i=1;i<=m;i++){
    		int p=find(a[i].x),q=find(a[i].y);
    		if(p!=q){
    			ans+=a[i].w;
    			add(a[i].x,a[i].y);
    		}
    	}
    }
    signed main(){
    	cin>>n>>m;
    	for(int i=1;i<=n;i++)
    		cin>>c[i],sw=min(sw,c[i]);
    	for(int i=1;i<=m;i++){
    		cin>>a[i].x>>a[i].y>>a[i].w;
    		a[i].w=a[i].w*2+c[a[i].x]+c[a[i].y];
    	}
    	kru();
    	cout<<ans+sw<<"\n";
    	return 0;
    }
    
    快速幂
    
    int ksm(int a,int b,int c){
    	int ans=1;
    	while(b){
    		if(b&1)ans=ans*a%c;
    		b>>=1,a=a*a%c;
    	}
    	return ans;
    }
    
    
    线性筛
    void init(int n){
    	memset(v,0,sizeof(v));
    	int tot=0;
    	for(int i=2;i<=n;i++){
    		if(!v[i]){
    			p[++tot]=i;
    		}
    		for(int k=1;k<=tot;k++){
    			if(i*p[k]>n)
    				break;
    			v[i*p[k]]=1;
    			if(i%p[k]==0)
    				break;
    		}
    	}
    }
    
    最短路(Dijkstra)
    
    #include <bits/stdc++.h>
    using namespace std;
    const int N=400050;
    struct node{
    	int v,w;
    };
    vector<node> v[N];
    bool operator<(node a,node b){
    	return a.w>b.w;
    }
    priority_queue<node> q;
    int n,m,s,dis[N];
    bool vis[N];
    void dij(int s){
    	for(int i=0;i<=n;i++)
    		dis[i]=INT_MAX;
    	dis[s]=0;
    	q.push({s,0});
    	while(!q.empty()){
    		node x=q.top();
    		q.pop();
    		if(vis[x.v]) continue;
    		vis[x.v]=1;
    		for(int i=0;i<v[x.v].size();i++){
    			node y=v[x.v][i];
    			if((long long)dis[x.v]+y.w<dis[y.v]){
    				dis[y.v]=dis[x.v]+y.w;
    				q.push({y.v,dis[y.v]});
    			}
    		}
    	}
    }
    signed main(){
    	cin>>n>>m>>s;
    	for(int i=1;i<=m;i++){
    		int x,y,w;
    		cin>>x>>y>>w;
    		v[x].push_back({y,w});
    	}
    	dij(s);
    	for(int i=1;i<=n;i++)
    		cout<<dis[i]<<" ";
    	return 0;
    }
    
    
    
    
    拓扑排序
    #include <bits/stdc++.h>
    using namespace std;
    const int N=505;
    int n,in[N],ans[N],tot;
    vector<int> v[N];
    queue<int> q;
    void topsort(){
    	for(int i=1;i<=n;i++){
    		if(in[i]==0){
    			ans[++tot]=i;
    			q.push(i);
    		}
    	}
    	while(!q.empty()){
    		int x=q.front();
    		q.pop();
    		for(int i=0;i<v[x].size();i++){
    			int y=v[x][i];
    			in[y]--;
    			if(in[y]==0){
    				ans[++tot]=y;
    				q.push(y);
    			}
    		}
    	}
    }
    signed main(){
    	cin>>n;
    	for(int i=1;i<=n;i++){
    		int y;
    		while(cin>>y){
    			if(y==0) break;
    			v[i].push_back(y);
    			in[y]++;
    		}
    	}
    	topsort();
    	for(int i=1;i<=n;i++)
    		cout<<ans[i]<<" ";
    	return 0;
    }
    
    
    快读快写
    #include<bits/stdc++.h>
    #define INPUT long long
    using namespace std;
    const int INPUT_Len = 50;
    inline INPUT Read(){char n;INPUT Re,f=1;while((n=getchar())<'0'||n>'9'){if(n==EOF)exit(0);if(n=='-')f=-1;}Re=n-48;while((n=getchar())>='0'&&n<='9')Re=Re*10+(n-48);return Re*f;}
    inline void Write(INPUT x, char End = '\n'){if(x==0){putchar('0');putchar(End);return;}else if (x < 0)putchar('-'),x=-x;char Prime[INPUT_Len];INPUT Ind=0;while(x){Prime[++Ind]=(char)(x%10+48);x /= 10;}for(int i=Ind;i>=1;i--)putchar(Prime[i]);putchar(End);}
    signed main(){
    	return 0;
    }
    
    
    优化大礼包
    再加上优化大礼包
    #include<bits/stdc++.h>
    #pragma GCC optimize(2) 
    // 如果CE,把第四行删了
    #pragma GCC optimize(3) 
    #pragma GCC optimize("Ofast")
    #pragma GCC optimize("inline") 
    #pragma GCC optimize("-fgcse") 
    #pragma GCC optimize("-fgcse-lm")
    #pragma GCC optimize("-fipa-sra")
    #pragma GCC optimize("-ftree-pre")
    #pragma GCC optimize("-ftree-vrp")
    #pragma GCC optimize("-fpeephole2")
    #pragma GCC optimize("-ffast-math")
    #pragma GCC optimize("-fsched-spec")
    #pragma GCC optimize("unroll-loops")
    #pragma GCC optimize("-falign-jumps")
    #pragma GCC optimize("-falign-loops")
    #pragma GCC optimize("-falign-labels")
    #pragma GCC optimize("-fdevirtualize")
    #pragma GCC optimize("-fcaller-saves")
    #pragma GCC optimize("-fcrossjumping")
    #pragma GCC optimize("-fthread-jumps")
    #pragma GCC optimize("-funroll-loops")
    #pragma GCC optimize("-fwhole-program")
    #pragma GCC optimize("-freorder-blocks")
    #pragma GCC optimize("-fschedule-insns")
    #pragma GCC optimize("inline-functions")
    #pragma GCC optimize("-ftree-tail-merge")
    #pragma GCC optimize("-fschedule-insns2")
    #pragma GCC optimize("-fstrict-aliasing")
    #pragma GCC optimize("-fstrict-overflow") 
    #pragma GCC optimize("-falign-functions") 
    #pragma GCC optimize("-fcse-skip-blocks") 
    #pragma GCC optimize("-fcse-follow-jumps") 
    #pragma GCC optimize("-fsched-interblock")
    #pragma GCC optimize("-fpartial-inlining") 
    #pragma GCC optimize("no-stack-protector")
    #pragma GCC optimize("-freorder-functions")
    #pragma GCC optimize("-findirect-inlining")
    #pragma GCC optimize("-frerun-cse-after-loop")
    #pragma GCC optimize("inline-small-functions")
    #pragma GCC optimize("-finline-small-functions")
    #pragma GCC optimize("-ftree-switch-conversion")
    #pragma GCC optimize("-foptimize-sibling-calls")
    #pragma GCC optimize("-fexpensive-optimizations")
    #pragma GCC optimize("-funsafe-loop-optimizations")
    #pragma GCC optimize("inline-functions-called-once")
    #pragma GCC optimize("-fdelete-null-pointer-checks")
    #define INPUT long long
    using namespace std;
    const int INPUT_Len = 50;
    inline INPUT Read(){char n;INPUT Re,f=1;while((n=getchar())<'0'||n>'9'){if(n==EOF)exit(0);if(n=='-')f=-1;}Re=n-48;while((n=getchar())>='0'&&n<='9')Re=Re*10+(n-48);return Re*f;}
    inline void Write(INPUT x, char End = '\n'){if(x==0){putchar('0');putchar(End);return;}else if (x < 0)putchar('-'),x=-x;char Prime[INPUT_Len];INPUT Ind=0;while(x){Prime[++Ind]=(char)(x%10+48);x /= 10;}for(int i=Ind;i>=1;i--)putchar(Prime[i]);putchar(End);}
    signed main(){
    	return 0;
    }
    

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