C++博客-purplest-随笔分类-网络流http://www.cppblog.com/purplest/category/17755.htmlzh-cnMon, 26 Sep 2011 21:49:15 GMTMon, 26 Sep 2011 21:49:15 GMT60poj 1459 Power Networkhttp://www.cppblog.com/purplest/archive/2011/09/26/156808.htmlpurplestpurplestMon, 26 Sep 2011 01:57:00 GMThttp://www.cppblog.com/purplest/archive/2011/09/26/156808.htmlhttp://www.cppblog.com/purplest/comments/156808.htmlhttp://www.cppblog.com/purplest/archive/2011/09/26/156808.html#Feedback0http://www.cppblog.com/purplest/comments/commentRss/156808.htmlhttp://www.cppblog.com/purplest/services/trackbacks/156808.html#include <iostream> #i...  阅读全文

purplest 2011-09-26 09:57 发表评论
]]>poj 1273 Drainage Ditcheshttp://www.cppblog.com/purplest/archive/2011/09/16/155971.htmlpurplestpurplestFri, 16 Sep 2011 15:41:00 GMThttp://www.cppblog.com/purplest/archive/2011/09/16/155971.htmlhttp://www.cppblog.com/purplest/comments/155971.htmlhttp://www.cppblog.com/purplest/archive/2011/09/16/155971.html#Feedback0http://www.cppblog.com/purplest/comments/commentRss/155971.htmlhttp://www.cppblog.com/purplest/services/trackbacks/155971.html
#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>

using namespace std;

const int N=210;
int n, m;
int mat[N][N];


int EKarp(int s, int t)
{
    queue < int > que;
    int flow[N][N], pre[N], temp[N], u, v, sum= 0;
    memset(flow, 0 , sizeof(flow));
    while (1)
    {
        que.push(s);
        memset(temp, 0, sizeof(temp));
        temp[s]= 0x7fffffff;
        while ( ! que.empty() )
        {
            u= que.front();
            que.pop();
            for ( v= 1 ; v <= n ; v++ )
                if ( !temp[v] && mat[u][v] > flow[u][v] )
                {
                    que.push(v);
                    temp[v]= temp[u] < mat[u][v]-flow[u][v] ? temp[u] : mat[u][v]-flow[u][v];
                    pre[v]= u;
                }
        }
        if ( temp[t] == 0 )
            break;
        for ( u = t ; u != s ; u=pre[u] )
        {
            flow[pre[u]][u] += temp[t];
            flow[u][pre[u]] -= temp[t];
        }
        sum+= temp[t];
    }
    return sum;
}

int main()
{
    while ( EOF != scanf("%d%d", &m, &n) )
    {
        int i, j, k, t;
        memset(mat, 0, sizeof(mat));
        for ( k = 0 ; k < m ; k++ )
        {
            scanf("%d%d%d", &i, &j, &t);
            mat[i][j] += t;
        }
        printf("%d\n", EKarp(1, n));
    }
    return 0;
}


purplest 2011-09-16 23:41 发表评论
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