Cod sursa(job #2373801)

Utilizator AndreiDeltaBalanici Andrei Daniel AndreiDelta Data 7 martie 2019 15:22:21
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.75 kb
#include <bits/stdc++.h>
#define Dim 1004
using namespace std;
ifstream f("maxflow.in");
ofstream g("maxflow.out");
int N,M,C[Dim][Dim],flow,a,b,c;
int T[Dim];
bool viz[Dim];
vector <int> V[Dim];

void init()
{
    for(int i=1;i<=N;i++)
    {
        viz[i]=0;
        T[i]=0;
    }
}

bool BFS()
{
    queue <int> qu;
    qu.push(1);
    viz[1]=1;
    T[1]=1;
    while(!qu.empty()&&viz[N]==0)
    {
        int nod=qu.front();
        qu.pop();
        viz[nod]=1;
        for(unsigned int i=0;i<V[nod].size()&&viz[N]==0;i++)
        {
            int vecin=V[nod][i];
            int cap=C[nod][vecin];
            if(!viz[vecin]&&cap>0)
            {
                T[vecin]=nod;
                viz[vecin]=1;
                qu.push(vecin);
            }
        }
    }
    return viz[N];
}

int main()
{
    f>>N>>M;
    for(int i=1;i<=M;i++)
    {
        f>>a>>b>>c;
        C[a][b]=c;
        //C[b][a]=(-1)*c;
        V[a].push_back(b);
        V[b].push_back(a);
    }
    while(BFS())
    {
        for(unsigned int i=0;i<V[N].size();i++)
        {
            int vecin=V[N][i];
            if(viz[vecin]==1&&C[vecin][N]>=0)
            {
                int minim=INT_MAX;
                T[N]=vecin;
                int poz=N;
                while(poz!=1)
                {
                    minim=min(minim,C[T[poz]][poz]);
                    poz=T[poz];
                }
                poz=N;
                flow+=minim;
                while(poz!=1)
                {
                    C[T[poz]][poz]-=minim;
                    C[poz][T[poz]]+=minim;
                    poz=T[poz];
                }
            }
        }
        init();
    }
    g<<flow;
    return 0;
}