Cod sursa(job #2954633)

Utilizator ralucarRogoza Raluca ralucar Data 14 decembrie 2022 22:15:17
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.66 kb
//ultima oara.
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define max_capacity 110001
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");

int n, m, x, y, cap, max_flow;
int capacity[1001][1001];
vector<int>parent, visited;
vector<int>adjacency_list[1001];
queue<int>q;

int bfs(){
    visited.assign(n+1, 0);
    parent.assign(n+1, 0);
    while(!q.empty()){
        q.pop();
    }
    q.push(1);
    visited[1]=1;
    parent[1]=1;
    while(!q.empty()){
        int node=q.front();
        q.pop();
        if(node==n){
            continue;
        }
        for(auto neighbour:adjacency_list[node]){
            if(visited[neighbour]==0 && capacity[node][neighbour]>0) {
                q.push(neighbour);
                parent[neighbour]=node;
                visited[neighbour]=1;
            }
        }
    }
    return visited[n];
}

int main() {
    fin>>n>>m;
    for(int i=1; i<=m; i++){
        fin>>x>>y>>cap;
        capacity[x][y] = cap;
        adjacency_list[x].push_back(y);
        adjacency_list[y].push_back(x);
    }
    while(bfs()){
        for(auto node: adjacency_list[n]){
            if(!visited[node])
                continue;
            parent[n]=node;
            int flow=max_capacity;
            for(node=n; node!=1; node=parent[node]){
                flow=min(flow, capacity[parent[node]][node]);
            }
            if(flow==0) continue;
            for(node=n; node!=1; node=parent[node]){
                capacity[parent[node]][node]-=flow;
                capacity[node][parent[node]]+=flow;
            }
            max_flow+=flow;
        }

    }
    fout<<max_flow;
    return 0;
}