Download Speed

#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;

const long long INF = 1e18;

int n, m;
vector<vector<long long>> capacity;
vector<vector<int>> adj;

long long bfs(int s, int t, vector<int>& parent) {
    fill(parent.begin(), parent.end(), -1);
    parent[s] = -2;
    queue<pair<int, long long>> q;
    q.push({s, INF});

    while (!q.empty()){
        int cur = q.front().first;
        long long flow = q.front().second;
        q.pop();

        for (int next : adj[cur]) {
            if (parent[next] == -1 && capacity[cur][next] > 0) {
                parent[next] = cur;
                long long new_flow = min(flow, capacity[cur][next]);
                if (next == t)
                    return new_flow;
                q.push({next, new_flow});
            }
        }
    }
    return 0;
}

long long maxflow(int s, int t){
    long long flow = 0;
    vector<int> parent(n + 1);
    long long new_flow;

    while ((new_flow = bfs(s, t, parent))){
        flow += new_flow;
        int cur = t;
        while (cur != s) {
            int prev = parent[cur];
            capacity[prev][cur] -= new_flow;
            capacity[cur][prev] += new_flow;
            cur = prev;
        }
    }
    return flow;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    if (!(cin >> n >> m)) return 0;

    capacity.assign(n + 1, vector<long long>(n + 1, 0));
    adj.resize(n + 1);

    for (int i = 0; i < m; i++) {
        int u, v;
        long long c;
        cin >> u >> v >> c;
        
        if (capacity[u][v] == 0 && capacity[v][u] == 0) {
            adj[u].push_back(v);
            adj[v].push_back(u);
        }
        capacity[u][v] += c;
    }
    cout << maxflow(1, n) << "\n";
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED