LeetCode/78. Subsets.cpp at master · Sharaf0/LeetCode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
class Solution {
    vector<vector<int>> ans;
    vector<int> res;
    vector<int> nums;
    int n;
public:
    void f(int index, int lastUsed) {
        if(index == -1) {
            ans.push_back(res);
            return;
        }
        for(int i = lastUsed + 1; i < n; i ++) {
            int temp = res[index];
            res[index] = nums[i];
            f(index - 1, i);
            res[index] = temp;
        }
    }

    vector<vector<int>> subsets(vector<int>& nums) {
        n = nums.size();
        this->nums = nums;
        ans.push_back({});
        for(int i = 1; i <= n; i ++) {
            res.clear();
            res.assign(i, 0);
            f(i - 1, -1);
        }
        return ans;
    }
};

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        int n = nums.size();
        vector<vector<int>> ans;
        vector<int> temp;
        for(int i = 0; i < (1<<n); i ++) {
            for(int j = 0; j < n; j ++) {
                if(((1 << j) & i)) {
                    temp.push_back(nums[j]);
                }
            }
            ans.push_back(temp);
            temp.clear();
        }
        return ans;
    }
};