Course Schedule

#include <vector>
#include <iostream>
#include <algorithm>
#include <stack>
using namespace std;

void topologicalSortUtil(int v, vector<vector<int>>& adj, vector<bool>& visited, stack<int>& Stack) {
    visited[v] = true;
    for (int i : adj[v]) {
        if (!visited[i]) {
            topologicalSortUtil(i, adj, visited, Stack);
        }
    }
    Stack.push(v);
}

void topologicalSort(vector<vector<int>>& adj, int n) {
    stack<int> Stack;
    vector<bool> visited(n, false);

    for (int i = 0; i < n; ++i) {
        if (!visited[i]) {
            topologicalSortUtil(i, adj, visited, Stack);
        }
    }

    if ((int)Stack.size() < n) {
        cout << "IMPOSSIBLE" << endl;
    } else {
        while (!Stack.empty()) {
            cout << Stack.top() + 1 << " "; 
            Stack.pop();
        }
        cout << endl;
    }
}

int main() {
    int n, m;
    cin >> n >> m;
    vector<vector<int>> adj(n);
    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        --a; --b;  
        adj[a].push_back(b);
    }
    topologicalSort(adj, n);
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER