Distinct Routes

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

using namespace std;
typedef long long ll;

int n, m;
struct Edge {
    int to;
    int cost;
};
vector<vector<pair<int, bool>>> adj;
vector<char> vis;
vector<int> path;
string out = "\n";

void add_edge(int a, int b) {}

bool simple_dfs(int node, int lenght) {

    if (node == n) {
        out += to_string(lenght) + "\n";
        return true;
    }

    vis[node] = 1;

    for (auto &to : adj[node]) {

        if (to.second || vis[to.first])
            continue;

        if (simple_dfs(to.first, lenght + 1)) {
            path.push_back(to.first);
            to.second = true;
            return true;
        }
    }
    return false;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n >> m;
    adj = vector<vector<pair<int, bool>>>(n + 1);
    vis.assign(n + 1, 0);

    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back({b, false});
    }

    int flow = 0;
    fill(vis.begin(), vis.end(), 0);
    while (simple_dfs(1, 1)) {
        flow++;
        out += "1 ";
        for (int i = path.size() - 1; i >= 0; i--) {
            out += to_string(path[i]) + " ";
        }
        path = vector<int>();
        out += "\n";
        fill(vis.begin(), vis.end(), 0);
    }

    cout << flow << out;
    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: WRONG ANSWER

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: WRONG ANSWER