先排序在dfs才會由小到大列喔

解法:

#include <iostream>

#include <vector>

#include <algorithm>

using namespace std;

void dfs(vector<int>& nums, vector<int>& current, int index, int m) {

if (current.size() == m) {

for (int num : current) {

cout << num << " ";

}

cout << endl;

return;

}

if (index >= nums.size()) {

return;

}

current.push_back(nums[index]);

dfs(nums, current, index+1, m);，//考慮當前數字

current.pop_back();

dfs(nums, current , index+1, m);//不考慮當前數字

}

int main() {

int n, m;

while (cin >> n && n != 0) {

vector<int> nums(n);

for (int i = 0; i < n; i++) {

cin >> nums[i];

}

cin >> m;

vector<int> current;

sort(nums.begin(), nums.end());

dfs(nums, current, 0, m);

cout << endl;

}

return 0;

}