Distinct Routes

input/code.cpp: In function 'int main()':
input/code.cpp:74:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |         for (int i = 0; i < path.size(); i++){
      |                         ~~^~~~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;

int n, m;
vector<int> to, cap;
vector<vector<int>> adj;
vector<char> vis;

int dfs(int v, int t, int f) {
    if (v == t) return f;
    vis[v] = 1;
    for (int e : adj[v]) {
        int u = to[e];
        if (!vis[u] && cap[e] > 0) {
            int r = dfs(u, t, min(f, cap[e]));
            if (r > 0) {
                cap[e] -= r;
                cap[e ^ 1] += r;
                return r;
            }
        }
    }
    return 0;
}

int main() {
    cin >> n >> m;
    adj.assign(n + 1, {});
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;

        adj[a].push_back(2 * i);     
        to.push_back(b); 
        cap.push_back(1);  

        adj[b].push_back(2 * i + 1); 
        to.push_back(a); 
        cap.push_back(0); 
    }

    int k = 0;
    while (true) {
        vis.assign(n + 1, 0);
        if (dfs(1, n, 1e9) == 0) break;
        k++;
    }

    vector<vector<int>> fl(n + 1);         
    for (int i = 0; i < m; i++)
        if (cap[2 * i] == 0) fl[to[2 * i + 1]].push_back(to[2 * i]);

    cout << k << endl;
    vector<int> ptr(n + 1, 0);
    for (int r = 0; r < k; r++) {
        vector<int> path = {1};
        vector<int> pos(n + 1, -1);
        pos[1] = 0;
        int v = 1;
        while (v != n) {
            int u = fl[v][ptr[v]++];       
            if (pos[u] != -1) {            
                while (path.back() != u) {
                    pos[path.back()] = -1;
                    path.pop_back();
                }
            } else {
                pos[u] = path.size();
                path.push_back(u);
            }
            v = u;
        }
        cout << path.size() << '\n';
        for (int i = 0; i < path.size(); i++){
            cout << path[i] << " ";
            if(i == n-1) cout << endl;
        }
    }
}

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

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED