Update 0046.全排列.md

problems/0046.全排列.md

@@ -227,24 +227,27 @@ class Solution:
 
 Go：
 ```Go
-var result [][]int
-func backtrack(nums,pathNums []int,used []bool){
-    if len(nums)==len(pathNums){
-        tmp:=make([]int,len(nums))
-        copy(tmp,pathNums)
-        result=append(result,tmp)
-        //result=append(result,pathNums)
-        return 
-    }
-    for i:=0;i<len(nums);i++{
-        if !used[i]{
-            used[i]=true
-            pathNums=append(pathNums,nums[i])
-            backtrack(nums,pathNums,used)
-            pathNums=pathNums[:len(pathNums)-1]
-            used[i]=false
-        }
-    }
+var res [][]int
+func permute(nums []int) [][]int {
+	res = [][]int{}
+	backTrack(nums,len(nums),[]int{})
+	return res
+}
+func backTrack(nums []int,numsLen int,path []int)  {
+	if len(nums)==0{
+		p:=make([]int,len(path))
+		copy(p,path)
+		res = append(res,p)
+	}
+	for i:=0;i<numsLen;i++{
+		cur:=nums[i]
+		path = append(path,cur)
+		nums = append(nums[:i],nums[i+1:]...)//直接使用切片
+		backTrack(nums,len(nums),path)
+		nums = append(nums[:i],append([]int{cur},nums[i:]...)...)//回溯的时候切片也要复原，元素位置不能变
+		path = path[:len(path)-1]
+
+	}
 }
 
 ```