Update 0047.全排列II.md Go 版本

problems/0047.全排列II.md

@@ -5,6 +5,7 @@
   <a href="https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ"><img src="https://img.shields.io/badge/知识星球-代码随想录-blue" alt=""></a>
 </p>
 <p align="center"><strong>欢迎大家<a href="https://mp.weixin.qq.com/s/tqCxrMEU-ajQumL1i8im9A">参与本项目</a>，贡献其他语言版本的代码，拥抱开源，让更多学习算法的小伙伴们收益！</strong></p>
+
 # 排列问题（二）
 
 ## 47.全排列 II
@@ -222,6 +223,43 @@ class Solution:
         return res
 ```
 
+Go：
+
+```go
+var res [][]int
+func permute(nums []int) [][]int {
+    res = [][]int{}
+    sort.Ints(nums)
+    dfs(nums, make([]int, 0), make([]bool, len(nums)))
+    return res
+}
+
+func dfs(nums, path []int, used []bool) {
+    if len(path) == len(nums) {
+        res = append(res, append([]int{}, path...))
+        return
+    }
+
+    m := make(map[int]bool)
+    for i := 0; i < len(nums); i++ {
+        // used 从剩余 nums 中选
+        if used[i] {
+            continue
+        }
+        // m 集合间去重
+        if _, ok := m[nums[i]]; ok {
+            continue
+        }
+        m[nums[i]] = true
+        path = append(path, nums[i])
+        used[i] = true
+        dfs(nums, path, used)
+        used[i] = false
+        path = path[:len(path)-1]
+    }
+}
+```
+
 Javascript:
 
 ```javascript