commit offer-38

Author: forgeyao

README.md

@@ -3,7 +3,6 @@ LeetCode
 
 ### LeetCode Algorithm
 
-
 | # | Title | Solution | Difficulty | Tag |
 |---| ----- | -------- | ---------- | ---------- |
 |5|[最长回文子串](https://leetcode-cn.com/problems/longest-palindromic-substring/)|[Go](./5-longestPalindrome/5-longestPalindrome.go)|中等|动态规划|
@@ -50,6 +49,12 @@ LeetCode
 |680|[验证回文字符串 Ⅱ](https://leetcode-cn.com/problems/valid-palindrome-ii/)|[Go](./680-validPalindrome/680-validPalindrome.go)|简单||
 |1332|[删除回文子序列](https://leetcode-cn.com/problems/remove-palindromic-subsequences/)|[Go](./1332-removePalindromeSub/1332-removePalindromeSub.go)|简单||
 
+### 剑指 Offer
+
+| # | Title | Solution | Difficulty | Tag |
+|---| ----- | -------- | ---------- | ---------- |
+|38|[字符串的排列](https://leetcode-cn.com/problems/zi-fu-chuan-de-pai-lie-lcof/)|[Go](./offer/38/38-permutation.go)|中等|递归|
+
 ### SQL
 
 | # | Title | Solution | Difficulty | Tag |

offer/38/38-permutation.go

@@ -0,0 +1,32 @@
+// https://leetcode-cn.com/problems/zi-fu-chuan-de-pai-lie-lcof/
+package main
+
+import "fmt"
+
+func permutation(s string) []string {
+	l := len(s)
+	if l == 1 {
+		return []string{s}
+	}
+
+	var ret []string
+	m := make(map[byte]int) // 字符去重
+	for i := 0; i < l; i++ {
+		if _, ok := m[s[i]]; ok {
+			continue
+		}
+		ss := permutation(s[0:i] + s[i+1:]) // 递归
+		for _, v := range ss {
+			ret = append(ret, string(s[i])+v)
+		}
+		m[s[i]] = 1
+	}
+	return ret
+}
+
+func main() {
+	s := []string{"a", "ab", "abc", "abcd", "aab"}
+	for _, v := range s {
+		fmt.Println("ret:", permutation(v))
+	}
+}