HDU 1532 Drainage Ditches 最大流 （Edmonds_Karp）

题目链接： http://acm.hdu.edu.cn/showproblem.php?pid=1532

感觉题意不清楚，不知道是不是个人英语水平问题。本来还以为需要维护入度和出度来找源点和汇点呢，看讨论才知道1就是起点，m就是汇点。。好想把代码写的工程化一点。

#include <stdio.h>
#include <string.h>
#include <queue>
#include <algorithm>
using namespace std;

const int INF = 0x3f3f3f3f;
int n, m;
int cap[210][210], flow[210][210], res[210], pre[210];
queue<int>que;

int Edmonds_Karp()
{
    while(!que.empty())
    {
        que.pop();
    }
    int flow_sum = 0;
    while(true)
    {
        memset(res, 0, sizeof(res));
        res[1] = INF;
        que.push(1);
        while(!que.empty())
        {
            int u = que.front();
            que.pop();
            for(int v = 1; v <= m; v++)
            {
                if(!res[v] && cap[u][v] > flow[u][v])
                {
                    pre[v] = u;
                    que.push(v);
                    res[v] = min(res[u], cap[u][v] - flow[u][v]);
                }
            }
        }
        if(res[m] == 0)break;
        for(int u = m; u != 1; u = pre[u])
        {
            flow[pre[u]][u] += res[m];
            flow[u][pre[u]] -= res[m];
        }
        flow_sum += res[m];
    }
    return flow_sum;
}

int main()
{
    int u, v, w;
    while(scanf("%d %d", &n, &m) != EOF)
    {
        memset(cap, 0, sizeof(cap));
        memset(flow, 0, sizeof(flow));
        for(int i = 0; i < n; i++)
        {
            scanf("%d %d %d", &u, &v, &w);
            cap[u][v] += w;
        }
        printf("%d
", Edmonds_Karp());
    }
    return 0;
}