提交时间:2024-03-06 13:09:28

运行 ID: 135682

#include<bits/stdc++.h> #define IOS cin.tie(0);cout.tie(0);ios::sync_with_stdio(false); using namespace std; int n; vector<vector<int>> ans; void dfs(int cur, vector<int> vec){ if (cur != 0)vec.push_back(cur); ans.push_back(vec); for (int i=cur+1; i<=n; i++)dfs(i, vec); } int main() { IOS cin >> n; dfs(0, vector<int>()); for (vector<int> vec : ans) { cout << "("; for (int x : vec)cout << (char)(x+'a'-1); cout << ")"<< endl; } return 0; }