hdu 1532 Drainage Ditches(最大流)

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题目链接：

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题目大意：

给出一些渠道，每个渠道有一个走向和容量，问最终汇集到溪流中的水的总量

题目分析：

裸裸的网络流的最大流，模板题

代码如下：

#include <iostream>#include <cstring>#include <algorithm>#include <cstdio>#include <queue>#define MAX 207#define INF 0x3f3f3f3fusing namespace std;int n,m;int s[MAX][MAX];int d[MAX];bool bfs ( ){    queue<int> q;    memset ( d , -1 , sizeof ( d ) );    d[1] = 0;    q.push ( 1 );    while ( !q.empty() )    {        int v = q.front();        q.pop();        for ( int i = 1 ; i <= n ; i++ )            if ( d[i] == -1 && s[v][i] )            {                d[i] = d[v]+1;                q.push ( i );            }    }    return d[n] != -1;}int dfs ( int v , int cur_flow ){    int dt = cur_flow;    if ( v == n ) return cur_flow;    for ( int i = 1 ; i <= n ; i++ )        if ( s[v][i] > 0 && d[v]+1 == d[i] )        {            int flow = dfs ( i , min ( dt , s[v][i] ) );            s[v][i] -= flow;            s[i][v] += flow;            dt -= flow;        }    return cur_flow - dt;}int dinic ( ){    int cur_flow, ans = 0;    while ( bfs() )    {        while ( cur_flow = dfs ( 1 , INF ) )            ans += cur_flow;    }    return ans;}int main ( ){    while ( ~scanf ( "%d%d" , &m , &n ) )    {        int u,v,c;        memset ( s , 0 , sizeof ( s ) );        while ( m-- )        {            scanf ( "%d%d%d" , &u , &v , &c );            s[u][v] += c;        }        //cout << "YES" << endl;        printf ( "%d\n" , dinic() );    }}

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