解法：

#include<iostream>
#include<vector>
using namespace std;
int arr[100][100];
int n;
int sta, des;
vector<int> path;
vector<vector<int>> res;
void dfs(vector<int> &a,int i) {a[i] = 1;path.push_back(i);if (i == des) {res.push_back(path);return;}for (int j = 0; j < n; j++) {if (arr[i][j]&&!a[j]) {dfs(a,j);path.pop_back();a[j] = 0;}}
}
int main() {cin >> n;vector<int> vis(n, 0);cin >> sta >> des;for (int i = 0; i < n; i++)for (int j = 0; j < n; j++)cin >> arr[i][j];dfs(vis,sta);for (int i = 0; i < res.size(); i++) {for (int j = 0; j < res[i].size(); j++) {cout << res[i][j];}cout << endl;}return 0;
}