Cod sursa(job #731413)

Utilizator test0Victor test0 Data 8 aprilie 2012 00:00:31
Problema Flux maxim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <stdio.h>
#include <algorithm>
#include <cstring>
#include <vector>
#define MAX 1001
using namespace std;

vector<int>u[MAX];
int c[MAX][MAX],f[MAX][MAX],n,m,k,cd[MAX],t[MAX];
bool viz[MAX];

bool bfs(){
    int x,y,i,j,k;
    memset(viz,0,sizeof(viz));
    cd[1]=viz[1]=k=i=1;
    for(i=1;i<=k;i++){
        x=cd[i];
        if(x==n)continue;
        for(j=0;j<u[x].size();j++){
            y=u[x][j];
            if(!viz[y]&&c[x][y]!=f[x][y]){
                viz[y]=1;
                cd[++k]=y;
                t[y]=x; } }
        }
    return viz[n];
}

int main(){
    int x,y,z,fmin,flux;
    freopen("maxflow.in","r",stdin);
    freopen("maxflow.out","w",stdout);
        scanf("%d %d",&n,&m);
        for(int i=1;i<=m;i++){
            scanf("%d %d %d",&x,&y,&z);
            c[x][y]=z;
            u[x].push_back(y);
            u[y].push_back(x);}
        for(flux=0;bfs();)
            for(int i=0;i<u[n].size();i++){
                x=u[n][i];
                if(c[x][n]==f[x][n]||!viz[x])continue;
                t[n]=x;
            fmin=MAX*MAX;
                for(x=n;x!=1;x=t[x])fmin=min(fmin,c[t[x]][x]-f[t[x]][x]);
            if(fmin==0)continue;
                for(x=n;x!=1;x=t[x]){
                    f[t[x]][x]+=fmin;
                    f[x][t[x]]-=fmin; }
            flux+=fmin;
            }
    printf("%d\n",flux);
}