Cod sursa(job #1051969)

Utilizator thewildnathNathan Wildenberg thewildnath Data 10 decembrie 2013 19:29:07
Problema Flux maxim Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.65 kb
#include<stdio.h>
#include<vector>
#include<queue>
#include<string.h>
#include<algorithm>
using namespace std;

#define NMAX 1005


vector<int> v[NMAX];
queue<int> q;
int n,m,cap[NMAX][NMAX],tata[NMAX];

void bfs()
{
    int x,i,y;
    q.push(1);
    tata[1]=-10;
    while(!q.empty())
    {
        if(tata[n]!=-1)
            break;
        x=q.front();
        q.pop();
        for(i=0;i<v[x].size();++i)
        {
            y=v[x][i];
            if(tata[y]==-1 && cap[x][y])
            {
                tata[y]=x;
                q.push(y);
            }
        }
    }

    while(!q.empty())
            q.pop();
}

int main()
{
    freopen("maxflow.in","r",stdin);
    freopen("maxflow.out","w",stdout);
    int i,j,k,x,y,sol=0,mini;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;++i)
    {
        scanf("%d%d%d",&x,&y,&cap[x][y]);
        v[y].push_back(x);
        v[x].push_back(y);
    }

    while(1)
    {
        memset(tata,-1,sizeof(tata));

        bfs();

        if(tata[n]==-1)
            break;
        for(i=1;i<=n;++i)
        {
            mini=cap[i][n];
            j=i;
            while(tata[j]>0)
            {
                mini=min(mini,cap[tata[j]][j]);
                j=tata[j];
            }

            if(!mini)
                continue;
            cap[i][n]-=mini;
            cap[n][i]+=mini;

            j=i;
            while(tata[j]>0)
            {
                cap[tata[j]][j]-=mini;
                cap[j][tata[j]]+=mini;
                j=tata[j];
            }
            sol+=mini;
        }

    }

    printf("%d\n",sol);

    return 0;
}