Cod sursa(job #759503)

Utilizator test13test13 test13 Data 18 iunie 2012 13:00:12
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.72 kb
#include <cstdio>
#include <vector>
#include <cstring>
#include <algorithm>
using namespace std;
#define MAX 1001
#define INF 0xffffff

vector<int>g[MAX];

int n,tt[MAX],cd[MAX],c[MAX][MAX],f[MAX][MAX]; //rezidual graph
bool viz[MAX];

bool bfs(){
    int p,u,x,y;
    cd[p=u=1]=1;
    memset(viz,0,sizeof(viz));
    viz[1]=1;
    while(p<=u)
    {
        x=cd[p];
        for(int i=0;i<g[x].size();i++)
        {
            y=g[x][i];
            if(!viz[y] && c[x][y] - f[x][y] > 0)
            {
                viz[y]=1;
                cd[++u]=y;
                tt[y]=x;
                if(y==n)return 1;
            }
        }
        p++;
    }
    return 0;
}

int main(){
    int m,x,y,z;
    freopen("maxflow.in","r",stdin);
    freopen("maxflow.out","w",stdout);
        scanf("%d %d",&n,&m);
        while(m--)
        {
            scanf("%d %d %d",&x,&y,&z);
            g[x].push_back(y); //arcul direct
            g[y].push_back(x); //arcul de intoarcere
            c[x][y]=z; //capacitatea arcului
        }
    int mflux = 0,flux = INF;
    for( ; bfs() ; flux = INF) //cit avem un drum de crestere
    {
        for(int x=n;x!=1;x=tt[x])flux=min(flux,c[tt[x]][x]-f[tt[x]][x]);
        if(flux!=0)
        {
            for(int x=n;x!=1;x=tt[x])
            {
                f[tt[x]][x]+=flux;
                f[x][tt[x]]-=flux;
            }
            mflux += flux;
        }
      /*  for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=n;j++)printf("%d ",f[i][j]); printf("\n");
        }
        printf("-----------------\n"); */
    }

    //bfs();

    //for(int x=n;x!=1;x=tt[x])printf("%d -> ",x);
    printf("%d\n",mflux);
    return 0;
}