Cod sursa(job #3003588)

Utilizator PingStrpewpewpac PingStr Data 15 martie 2023 20:05:47
Problema Flux maxim Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.47 kb
#include <bits/stdc++.h>
using namespace std;

ifstream fin("maxflow.in");
ofstream fout("maxflow.out");

const int N = 1e3 + 1;
const int INF = 1e7;

vector<int> gr[N];
int n, m, x, y, z;
int parnt[N]; 
int cap[N][N];

bool bfs(int s, int t)
{
    memset(parnt, 0, sizeof(parnt));
    parnt[s] = 1;
    queue<int> q;
    q.push(s);
    while(!q.empty())
    {
        int nod = q.front();
        q.pop();
        for (auto i: gr[nod])
        {
            if (parnt[i] == 0 && cap[nod][i] > 0)
            {
                parnt[i] = nod;
                q.push(i);
                if(i == t)
                    return true;
            }
        }
    }
    return 0;
}

int maxflow(int s, int t)
{
    int flow = 0, minflow;
    while(bfs(1, n))
    {
        minflow = INF;
        for (auto i: gr[t])
        {
            int nod = i;
            if (parnt[nod] == 0 || cap[nod][t] <= 0) continue;

            nod = t;
            while (nod != s)
            {
                minflow = min(minflow, cap[parnt[nod]][nod]);
                nod = parnt[nod];
            }
            nod = t;
            while (nod != s)
            {
                cap[parnt[nod]][nod] -= minflow;
                nod = parnt[nod];
            }
            flow += minflow;
        }
    }
    return flow;
}


int main()
{
    fin>>n>>m;
    for (int i = 1; i <= m; i++)
    {
        fin>>x>>y>>z;
        gr[x].push_back(y);
        gr[y].push_back(x);
        cap[x][y] = z;
    }
    fout<<maxflow(1, n);
}