Cod sursa(job #3139480)

Utilizator matwudemagogul matwu Data 28 iunie 2023 18:27:20
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.83 kb
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("O3")
#pragma GCC optimize ("O2")
#pragma GCC optimize ("O1")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize ("fast-math")
#define ezurect int T; cin >> T; while(T--){solve();}
const int N = 1e3 + 1, M = 4e5 + 1, mod = 666013;

int n, m;
vector<int> liste[N];
vector<vector<int>> cost(N, vector<int>(N)), f(N, vector<int>(N));
vector<int> p(N);

int bfs(){
    queue<int> q;
    q.push(1);
    p.assign(N, -1);
    p[1] = 0;

    while(!q.empty()){
        int nod = q.front();
        q.pop();
        if(nod == n){
            continue;
        }
        for(auto i : liste[nod]){
            if(p[i] == -1 && f[nod][i] < cost[nod][i]){
                p[i] = nod;
                q.push(i);
            }
        }
    }
    if(p[n] < 0) return 0;
    return 1;
}
int MaxFlux(){
    int maxflux = 0;
    while(bfs()){
        int t = n;
        for(auto i : liste[t]){
            if(f[i][t] == cost[i][t] || p[i] == -1){
                continue;
            }
            p[t] = i;
            int minim = 1e9;
            for(int j = t; j != 1; j = p[j]){
                minim = min(minim, cost[p[j]][j] - f[p[j]][j]);
            }
            for(int j = t; j != 1; j = p[j]){
                f[p[j]][j] += minim;
                f[j][p[j]] -= minim;
            }
            maxflux += minim;
        }
    }
    return maxflux;
}
int main(){
    ifstream fin("maxflow.in");
    ofstream fout("maxflow.out");
    fin.tie(0)->sync_with_stdio(0);
    fin >> n >> m;
    for(int i = 1; i <= m; i++){
        int u, v, c;
        fin >> u >> v >> c;
        liste[u].push_back(v);
        liste[v].push_back(u);
        cost[u][v] = c;
    }

    fout << MaxFlux();
}