Cod sursa(job #1245324)

Utilizator gapdanPopescu George gapdan Data 18 octombrie 2014 22:35:21
Problema Flux maxim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.83 kb
#include<cstdio>
#include<cstring>
#include<queue>
#define INF 0x3f3f3f3f
#define min(a,b) (a<b?a:b)
using namespace std;
queue<int>q;
vector<int>v[1001];
int f[1001][1001],c[1001][1001];
int tata[1001],flux,x,y,z,n,m,i;
int viz[1001];
int flmin;
void cauta()
{
    int varf;
    q.push(1);
    memset(viz,0,sizeof(viz));
    viz[1]=1;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        if (nod==n) continue;
        for (i=0;i<v[nod].size();++i)
        {
            varf=v[nod][i];
            if(c[nod][varf]==f[nod][varf] || viz[varf]) continue;
            viz[varf]=1;
            q.push(varf);
            tata[varf]=nod;
        }

    }
}
int main()
{
    freopen("maxflow.in","r",stdin);
    freopen("maxflow.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (i=1;i<=m;++i)
    {
        scanf("%d%d%d",&x,&y,&z);
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y]=z;
    }
    flux=0;
    while (true) //cat timp avem retea reziduala
    {
        cauta();
        if (viz[n]==0) break;
        for (i=0;i<v[n].size();++i)
        {
            int nod=v[n][i];
             if (f[nod][n]==c[nod][n] || !viz[nod]) continue;
            //daca fluxul drumului este egal cu capacitatea
            //sau drumul nu face parte din reteaua reziduala
            tata[n]=nod;
            flmin=INF;
            //calculeaza fluxul minim din reatea
            for (nod=n;nod!=1;nod=tata[nod])
                flmin=min(flmin,c[tata[nod]][nod]-f[tata[nod]][nod]);
            //reimprospateaza reteaua
            for (nod=n;nod!=1; nod=tata[nod])
            {
                f[tata[nod]][nod]+=flmin;
                f[nod][tata[nod]]-=flmin;
            }
            flux+=flmin;
        }
    }
    printf("%d\n",flux);
    return 0;
}