Cod sursa(job #1653562)

Utilizator ZeBuGgErCasapu Andreas ZeBuGgEr Data 16 martie 2016 10:39:55
Problema Flux maxim Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.04 kb
#include<cstdio>
#include<vector>
#include<queue>

using namespace std;

vector<int> con[1010];

int n,m,x,y,z,res;
int cap[1010][1010],flux[1010][1010],tata[1010];
bool viz[1010];
queue<int> q;

int bfs()
{
    for(int i=1;i<=1000;i++)
    {
        viz[i]=0;
    }
    viz[1]=1;
    q.push(1);

    int curr,next;

    while(!q.empty())
    {
        curr=q.front();
        if(curr!=n)
        {
        for(vector<int>::iterator it=con[curr].begin();it!=con[curr].end();it++)
        {
            next=*it;
            if(flux[curr][next]<cap[curr][next]&&viz[next]==0)
            {
                viz[next]=1;
                q.push(next);
                tata[next]=curr;
            }
        }
        }
        q.pop();
    }

    return viz[n];
}

int main()
{
    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);
        con[x].push_back(y);
        con[y].push_back(x);
        cap[x][y]+=z;

    }

    while(bfs())
    {
        for(vector<int>::iterator it=con[n].begin();it!=con[n].end();it++)
        {
            int curr=*it;
            if(flux[curr][n]<cap[curr][n]&&viz[curr]==1)
            {
                int minfl=cap[curr][n]-flux[curr][n];
                while(tata[curr]!=0)
                {
                    if(cap[tata[curr]][curr]-flux[tata[curr]][curr]<minfl)
                    {
                        minfl=cap[tata[curr]][curr]-flux[tata[curr]][curr];
                    }
                    curr=tata[curr];
                }

                res+=minfl;
                curr=*it;
                flux[curr][n]+=minfl;
                flux[n][curr]-=minfl;
                while(tata[curr]!=0)
                {
                    flux[tata[curr]][curr]+=minfl;
                    flux[curr][tata[curr]]-=minfl;
                    curr=tata[curr];
                }
            }
        }
    }
    printf("%d",res);
}