Cod sursa(job #2651400)

Utilizator aser.cobaschiCobaschi Aser aser.cobaschi Data 22 septembrie 2020 16:16:35
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.26 kb
#include <bits/stdc++.h>

using namespace std;
ifstream f("maxflow.in");
ofstream g("maxflow.out");
const int N = 1005;
int n,m,x,y,c,Flux,T[N],C[N][N],F[N][N];
vector<int> v[N];
bool bfs();
void upd();
int main()
{
    f>>n>>m;
    for(int i=1; i<=m; i++)
    {
        f>>x>>y>>c;
        v[x].push_back(y);
        v[y].push_back(x);
        C[x][y]=c;
    }
    while(bfs())
        upd();
    g<<Flux;
    return 0;
}
bool bfs()
{
    fill(T+1,T+n+1,0);
    T[1]=-1;
    queue<int> q;
    q.push(1);
    while(q.size())
    {
        int nod = q.front();
        q.pop();
        for(auto vec:v[nod])
            if(!T[vec])
                if(C[nod][vec]-F[nod][vec]>0)
                {
                    if(vec==n)
                        return true;
                    T[vec]=nod;
                    q.push(vec);
                }

    }
    return false;
}
void upd()
{
    for(int k=1;k<n;k++)
    if(T[k]&&C[k][n]-F[k][n]>0)
    {
        T[n]=k;
        int flux=1<<30;
        for(int i=T[n],j=n;j!=1;i=T[i],j=T[j])
            flux=min(flux,C[i][j]-F[i][j]);
        Flux+=flux;
        for(int i=T[n],j=n;j!=1;i=T[i],j=T[j])
        {
            F[i][j]+=flux;
            F[j][i]-=flux;
        }
    }

}