Cod sursa(job #2847650)

Utilizator alexdumitruAlexandru Dumitru alexdumitru Data 11 februarie 2022 10:42:33
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.87 kb
#include <bits/stdc++.h>
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
vector<int> g[1005];
int t[1005];
bool sel[1005];
int f[1005][1005];
int c[1005][1005];
int n,m,x,y;
int i,j;
int flux_total;
bool bfs(int x, int y)
{
    queue<int> q;
    for(int i=1;i<=n;i++)
    {
        sel[i]=0;
        t[i]=-1;
    }
    q.push(x);
    sel[x]=1;
    t[x]=0;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(auto it:g[nod])
            if(!sel[it])
                if(f[nod][it]<c[nod][it])
                {
                    q.push(it);
                    t[it]=nod;
                    sel[it]=1;
                }
    }
    return sel[y];
}
signed main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
        fin>>c[x][y];
    }
    int cnt=0;
    while(bfs(1,n))
    {
        //cout<<++cnt<<'\n';
        for(auto it:g[n])
        {
            if(t[it]!=-1)
            {
                int nod=it;
                int flux_curent=c[nod][n]-f[nod][n];
                while(nod!=1)
                {
                    int tata=t[nod];
                    flux_curent=min(flux_curent,c[tata][nod]-f[tata][nod]);
                    nod=tata;
                    //cout<<nod<<' ';
                }
                flux_total+=flux_curent;
                nod=it;
                f[nod][n]+=flux_curent;
                f[n][nod]-=flux_curent;
                while(nod!=1)
                {
                    int tata=t[nod];
                    f[tata][nod]+=flux_curent;
                    f[nod][tata]-=flux_curent;
                    nod=tata;
                    //cout<<nod<<' ';
                }
            }
        }
    }
    fout<<flux_total<<'\n';
    return 0;
}