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feat: add solutions to lc/lcof2 problem: Subsets
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‎.github/workflows/compress.yml

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@@ -8,6 +8,7 @@ on:
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- "**.jpeg"
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- "**.png"
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- "**.webp"
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workflow_dispatch:
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jobs:
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compress:

‎lcof2/剑指 Offer II 079. 所有子集/README.md

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@@ -43,22 +43,121 @@
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<!-- 这里可写通用的实现逻辑 -->
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回溯法的基本模板：
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```py
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res = []
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path = []
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def backtrack(未探索区域, res, path):
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if path 满足条件:
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res.add(path) # 深度拷贝
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# return # 如果不用继续搜索需要 return
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for 选择 in 未探索区域当前可能的选择:
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if 当前选择符合要求:
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path.add(当前选择)
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backtrack(新的未探索区域, res, path)
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path.pop()
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```
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4663
<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def subsets(self, nums: List[int]) -> List[List[int]]:
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res = []
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def dfs(i, n, t):
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res.append(t.copy())
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if i == n:
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return
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for j in range(i, n):
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t.append(nums[j])
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dfs(j + 1, n, t)
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t.pop()
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dfs(0, len(nums), [])
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return res
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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public List<List<Integer>> subsets(int[] nums) {
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List<List<Integer>> res = new ArrayList<>();
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dfs(0, nums, new ArrayList<>(), res);
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return res;
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}
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private void dfs(int i, int[] nums, List<Integer> t, List<List<Integer>> res) {
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res.add(new ArrayList<>(t));
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if (i == nums.length) {
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return;
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}
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for (int j = i; j < nums.length; ++j) {
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t.add(nums[j]);
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dfs(j + 1, nums, t, res);
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t.remove(t.size() - 1);
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}
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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vector<vector<int>> subsets(vector<int>& nums) {
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vector<vector<int>> res;
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vector<int> t;
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dfs(0, nums, t, res);
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return res;
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}
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void dfs(int i, vector<int>& nums, vector<int> t, vector<vector<int>>& res) {
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res.push_back(t);
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if (i == nums.size()) return;
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for (int j = i; j < nums.size(); ++j)
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{
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t.push_back(nums[j]);
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dfs(j + 1, nums, t, res);
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t.pop_back();
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}
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}
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};
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```
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### **Go**
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```go
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func subsets(nums []int) [][]int {
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var res [][]int
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var t []int
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dfs(0, nums, t, &res)
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return res
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}
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func dfs(i int, nums, t []int, res *[][]int) {
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cp := make([]int, len(t))
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copy(cp, t)
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*res = append(*res, cp)
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if i == len(nums) {
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return
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}
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for j := i; j < len(nums); j++ {
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t = append(t, nums[j])
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dfs(j+1, nums, t, res)
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t = t[:len(t)-1]
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}
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}
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```
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### **...**

‎lcof2/剑指 Offer II 079. 所有子集/Solution.cpp

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@@ -0,0 +1,20 @@
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class Solution {
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public:
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vector<vector<int>> subsets(vector<int>& nums) {
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vector<vector<int>> res;
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vector<int> t;
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dfs(0, nums, t, res);
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return res;
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}
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void dfs(int i, vector<int>& nums, vector<int> t, vector<vector<int>>& res) {
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res.push_back(t);
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if (i == nums.size()) return;
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for (int j = i; j < nums.size(); ++j)
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{
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t.push_back(nums[j]);
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dfs(j + 1, nums, t, res);
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t.pop_back();
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}
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}
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};

‎lcof2/剑指 Offer II 079. 所有子集/Solution.go

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@@ -0,0 +1,20 @@
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func subsets(nums []int) [][]int {
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var res [][]int
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var t []int
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dfs(0, nums, t, &res)
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return res
6+
}
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8+
func dfs(i int, nums, t []int, res *[][]int) {
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cp := make([]int, len(t))
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copy(cp, t)
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*res = append(*res, cp)
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if i == len(nums) {
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return
14+
}
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for j := i; j < len(nums); j++ {
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t = append(t, nums[j])
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dfs(j+1, nums, t, res)
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t = t[:len(t)-1]
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}
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}

‎lcof2/剑指 Offer II 079. 所有子集/Solution.java

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
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class Solution {
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public List<List<Integer>> subsets(int[] nums) {
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List<List<Integer>> res = new ArrayList<>();
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dfs(0, nums, new ArrayList<>(), res);
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return res;
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}
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8+
private void dfs(int i, int[] nums, List<Integer> t, List<List<Integer>> res) {
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res.add(new ArrayList<>(t));
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if (i == nums.length) {
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return;
12+
}
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for (int j = i; j < nums.length; ++j) {
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t.add(nums[j]);
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dfs(j + 1, nums, t, res);
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t.remove(t.size() - 1);
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}
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}
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}

‎lcof2/剑指 Offer II 079. 所有子集/Solution.py

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
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class Solution:
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def subsets(self, nums: List[int]) -> List[List[int]]:
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res = []
4+
5+
def dfs(i, n, t):
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res.append(t.copy())
7+
if i == n:
8+
return
9+
for j in range(i, n):
10+
t.append(nums[j])
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dfs(j + 1, n, t)
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t.pop()
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14+
dfs(0, len(nums), [])
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return res

‎solution/0000-0099/0078.Subsets/README.md

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@@ -36,7 +36,6 @@
3636
<li><code>nums</code> 中的所有元素 <strong>互不相同</strong></li>
3737
</ul>
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39-
4039
## 解法
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<!-- 这里可写通用的实现逻辑 -->
@@ -67,15 +66,18 @@ def backtrack(未探索区域, res, path):
6766
```python
6867
class Solution:
6968
def subsets(self, nums: List[int]) -> List[List[int]]:
70-
def dfs(nums, i, res, path):
71-
res.append(copy.deepcopy(path))
72-
while i < len(nums):
73-
path.append(nums[i])
74-
dfs(nums, i + 1, res, path)
75-
path.pop()
76-
i += 1
77-
res, path = [], []
78-
dfs(nums, 0, res, path)
69+
res = []
70+
71+
def dfs(i, n, t):
72+
res.append(t.copy())
73+
if i == n:
74+
return
75+
for j in range(i, n):
76+
t.append(nums[j])
77+
dfs(j + 1, n, t)
78+
t.pop()
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80+
dfs(0, len(nums), [])
7981
return res
8082
```
8183

@@ -86,24 +88,75 @@ class Solution:
8688
```java
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class Solution {
8890
public List<List<Integer>> subsets(int[] nums) {
89-
List<Integer> path = new ArrayList<>();
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List<List<Integer>> res = new ArrayList<>();
91-
dfs(nums, 0, res, path);
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dfs(0, nums, new ArrayList<>(), res);
9293
return res;
9394
}
9495

95-
private void dfs(int[] nums, int i, List<List<Integer>> res, List<Integer> path) {
96-
res.add(new ArrayList<>(path));
97-
while (i < nums.length) {
98-
path.add(nums[i]);
99-
dfs(nums, i + 1, res, path);
100-
path.remove(path.size() - 1);
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++i;
96+
private void dfs(int i, int[] nums, List<Integer> t, List<List<Integer>> res) {
97+
res.add(new ArrayList<>(t));
98+
if (i == nums.length) {
99+
return;
100+
}
101+
for (int j = i; j < nums.length; ++j) {
102+
t.add(nums[j]);
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dfs(j + 1, nums, t, res);
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t.remove(t.size() - 1);
102105
}
103106
}
104107
}
105108
```
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110+
### **C++**
111+
112+
```cpp
113+
class Solution {
114+
public:
115+
vector<vector<int>> subsets(vector<int>& nums) {
116+
vector<vector<int>> res;
117+
vector<int> t;
118+
dfs(0, nums, t, res);
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return res;
120+
}
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122+
void dfs(int i, vector<int>& nums, vector<int> t, vector<vector<int>>& res) {
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res.push_back(t);
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if (i == nums.size()) return;
125+
for (int j = i; j < nums.size(); ++j)
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{
127+
t.push_back(nums[j]);
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dfs(j + 1, nums, t, res);
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t.pop_back();
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}
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}
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};
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```
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### **Go**
136+
137+
```go
138+
func subsets(nums []int) [][]int {
139+
var res [][]int
140+
var t []int
141+
dfs(0, nums, t, &res)
142+
return res
143+
}
144+
145+
func dfs(i int, nums, t []int, res *[][]int) {
146+
cp := make([]int, len(t))
147+
copy(cp, t)
148+
*res = append(*res, cp)
149+
if i == len(nums) {
150+
return
151+
}
152+
for j := i; j < len(nums); j++ {
153+
t = append(t, nums[j])
154+
dfs(j+1, nums, t, res)
155+
t = t[:len(t)-1]
156+
}
157+
}
158+
```
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107160
### **...**
108161

109162
```

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