初学网络流——最大流模板（dinic）

多组输入只需把vector清零即可
o(￣︶￣)o

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
const int MAXN = 1e4+10;
const double EPS = 1e-12;

int n,m,s,t,cas,T;
struct edge{
    int to,cap,rev;
};
vector<edge>G[MAXN];
int level[MAXN],iter[MAXN];

inline void addedge(int from,int to,int cap){
    G[from].push_back(edge{to,cap,G[to].size()});
    G[to].push_back(edge{from,0,G[from].size()-1});
}

inline bool bfs(){
    memset(level,0,sizeof(level));
    queue<int>q;
    level[s]=1;
    q.push(s);
    while(!q.empty()){
        int x=q.front();q.pop();
        for(int i=0;i<G[x].size();i++){
            edge &e=G[x][i];
            if(e.cap>0&&level[e.to]==0){
                level[e.to]=level[x]+1;
                q.push(e.to);
            }
        }
    }
    return level[t]==0 ? 0 : 1;
}

inline int dfs(int x,int flow){
    if(x==t)return flow;
    for(int &i=iter[x];i<G[x].size();i++){
        edge &e=G[x][i];
        if(e.cap>0&&level[e.to]>level[x]){
            int d=dfs(e.to,min(flow,e.cap));
            if(d>0){
                e.cap-=d;
                G[e.to][e.rev].cap+=d;
                return d;
            }
        }
    }
    return 0;
}

int main()
{
    scanf("%d %d %d %d",&n,&m,&s,&t);
    int u,v,w;
    for(int i=1;i<=m;i++){
        scanf("%d %d %d",&u,&v,&w);
        addedge(u,v,w);
    }
    int ans=0;
    while(bfs()){
        memset(iter,0,sizeof(iter));
        int now;
        while((now=dfs(s,1e9)))
            ans+=now;
    }
    printf("%d
",ans);
}