Dinic

/***********************************************\ |Author: YMC |Created Time: 2014/4/15 19:42:23 |File Name: Dinic.cpp |Description: \***********************************************/#include <iostream>#include <cstdio>#include <cmath>#include <cstdlib>#include <string>#include <cstring>#include <algorithm>#include <vector>#include <list>#include <map>#include <set>#include <deque>#include <queue>#include <stack>#define MAX_V 1005using namespace std;#define INF 10000000struct edge{    int to,cap,rev;};vector <edge> G[MAX_V];int level[MAX_V];int iter[MAX_V];//当前弧，之前用过的已经没用了void add_edge(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});}void bfs(int s){    memset(level,-1,sizeof(level));    queue<int> que;    level[s] = 0;    que.push(s);    while(!que.empty()){        int v = que.front();        que.pop();        for(int i=0;i<G[v].size();++i){            edge &e = G[v][i];            if(e.cap > 0 && level[e.to]<0){                level[e.to] = level[v] + 1;                que.push(e.to);            }        }    }}int dfs(int v,int t,int f){    if(v == t) return f;    for(int &i = iter[v];i         edge &e = G[v][i];        if(e.cap > 0 && level[v] < level[e.to]){            int d = dfs(e.to,t,min(f,e.cap));            if(d > 0){                e.cap -= d;                G[e.to][e.rev].cap += d;                return d;            }        }      }    return 0;        //千万注意不要漏了返回0，不然会无限循环。 }int max_flow(int s,int t){    int flow = 0;    for(;;){        bfs(s);        //cout<<"haha";        if(level[t] < 0) return flow;        memset(iter,0,sizeof(iter));        int f;        while((f = dfs(s,t,INF)) > 0){            flow += f;        }    }    return flow;}int main() {    //freopen("input.txt","r",stdin);     int n;    scanf("%d",&n);    int from,to,cap;    int s,t;    while(n–){        scanf("%d%d%d",&from,&to,&cap);        add_edge(from,to,cap);    }    scanf("%d%d",&s,&t);    printf("%d\n",max_flow(s,t));    return 0;}/*74 1 101 3 61 2 63 2 34 2 22 5 53 5 84 511请按任意键继续. . .*/