POJ 1273 最大流

裸題，可以用vector儲存鄰接表來使代碼變得簡潔。
輸入新的一組測試數據的時候要記得清空。
下爲Dinic算法的代碼。

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <string>
#include <map>
#include <queue>
#include <vector>
#define N 210
#define ll long long
#define INF 0x7fffffff
using namespace std;
struct Edge{
    int from,to,cap,flow;
    Edge(int a=0,int b=0,int c=0, int d=0){
        from = a,to = b,cap = c,flow = d;
    }
};
vector<Edge>edges;
vector<int>G[N];
int n,m,s,t;
void addedge(int from, int to,int cap){
    edges.push_back(Edge(from,to,cap,0));
    edges.push_back(Edge(to,from,0,0));
    int m = edges.size();
    G[from].push_back(m-2);
    G[to].push_back(m-1);
}
bool vis[N];
int cur[N],deep[N];

bool bfs(){
    memset(vis,0,sizeof(vis));
    queue<int>que;
    que.push(s);
    deep[s] = 0;
    vis[s] = 1;
    while (!que.empty())
    {
        int x = que.front();que.pop();
        for(int i=0;i<G[x].size();i++){
            Edge& e = edges[G[x][i]];
            if(!vis[e.to] && e.cap > e.flow){//無視沒有殘量的弧
                vis[e.to] = 1;deep[e.to] = deep[x]+1;
                que.push(e.to);
            }
        }
    }
    return vis[t];
}

int dfs(int x,int a){
    if(x == t || a == 0){
        return a;
    }
    int flow = 0,f;
    for(int& i = cur[x];i<G[x].size();i++){
        Edge& e = edges[G[x][i]];
        if(deep[x]+1 == deep[e.to] && (f = dfs(e.to,min(a,e.cap - e.flow))) > 0){//可以流
            e.flow+=f;
            edges[G[x][i]^1].flow-=f;
            flow+=f;
            a-=f;
            if(a == 0){
                break;
            }
        }

    }
    return flow;
}

ll Maxflow(){
    ll flow = 0;
    while (bfs())
    {
        memset(cur,0,sizeof(cur));
        flow+=dfs(s,INF);
    }
    return flow;
}
int main()
{
    int i,j,l,x,y,z;
    while (~scanf("%d",&n))
    {
        for(i=0;i<=N;i++){
            G[i].clear();
        }
        edges.clear();
        scanf("%d",&m);
        s = 1;t = m;
        for(i=1;i<=n;i++){
            scanf("%d%d%d",&x,&y,&z);
            addedge(x,y,z);
        }
        printf("%lld\n",Maxflow());
    }
    return 0;
}