HDU 3549 Flow Problem ( 最大流 -EK 算法)

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C++，G++的读取速度差距也太大了

Flow Problem

题意：n，m表示n个点m条有向带权边

问：从1-n最大流多少

裸最大流，拿来练手，挺不错的

#include <iostream>#include <cstdlib>#include <cstdio>#include <cstring>#include <queue>#include <algorithm>const int N = 210;#define MIN INT_MIN#define MAX INT_MAX#define LL long longusing namespace std;int max(int a,int b){if(a>b)return a; else return b;}int min(int a,int b){if(a<b)return a; else return b;}int c[100][100];int re[100];int f[100][100];int p[100],n,m;void init(){    for(int i = 0;i<=n;i++)    {        for(int j = 0;j<=n;j++)        {            c[i][j] = f[i][j] = 0;        }        p[i] = 0;    }}void EK(int s,int t){    queue<int >q;    while(q.empty()==false) q.pop();    int sum = 0;    while(1)    {        memset(re,0,sizeof(re));        q.push(s);        re[s] = MAX;        p[s] = -1;        while(!q.empty())        {            int u = q.front();            q.pop();            for(int i = 1;i<=n;i++)            {                if(!re[i] && f[u][i] < c[u][i])                {                    q.push(i);                    p[i] = u;                    re[i] = min(re[u],c[u][i]-f[u][i]);                }            }        }        if(re[t]==0) break;        for(int st = t;st!=s;st = p[st])        {            f[p[st]][st] += re[t];            f[st][p[st]] -= re[t];        }        sum += re[t];    }    printf("%d\n",sum);}int main(){    int t,C=0,a,b,w;    scanf("%d",&t);    while(t--)    {        C++;        scanf("%d%d",&n,&m);        init();        for(int i = 0;i<m;i++)        {            scanf("%d%d%d",&a,&b,&w);            c[a][b] += w;        }        printf("Case %d: ",C);        EK(1,n);    }    return 0;}

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