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website/content/ChapterFour/0131.Palindrome-Partitioning.md

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+# [131. Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/)
+
+
+## 题目
+
+Given a string *s*, partition *s* such that every substring of the partition is a palindrome.
+
+Return all possible palindrome partitioning of *s*.
+
+**Example**:
+
+    Input: "aab"
+    Output:
+    [
+      ["aa","b"],
+      ["a","a","b"]
+    ]
+
+## 题目大意
+
+给定一个字符串 s，将 s 分割成一些子串，使每个子串都是回文串。返回 s 所有可能的分割方案。
+
+## 解题思路
+
+- 要求输出一个字符串可以被拆成回文串的所有解，DFS 递归求解即可。
+
+
+## 代码
+
+```go
+
+package leetcode
+
+// 解法一
+func partition131(s string) [][]string {
+	if s == "" {
+		return [][]string{}
+	}
+	res, pal := [][]string{}, []string{}
+	findPalindrome(s, 0, "", true, pal, &res)
+	return res
+}
+
+func findPalindrome(str string, index int, s string, isPal bool, pal []string, res *[][]string) {
+	if index == len(str) {
+		if isPal {
+			tmp := make([]string, len(pal))
+			copy(tmp, pal)
+			*res = append(*res, tmp)
+		}
+		return
+	}
+	if index == 0 {
+		s = string(str[index])
+		pal = append(pal, s)
+		findPalindrome(str, index+1, s, isPal && isPalindrome131(s), pal, res)
+	} else {
+		temp := pal[len(pal)-1]
+		s = pal[len(pal)-1] + string(str[index])
+		pal[len(pal)-1] = s
+		findPalindrome(str, index+1, s, isPalindrome131(s), pal, res)
+		pal[len(pal)-1] = temp
+		if isPalindrome131(temp) {
+			pal = append(pal, string(str[index]))
+			findPalindrome(str, index+1, temp, isPal && isPalindrome131(temp), pal, res)
+			pal = pal[:len(pal)-1]
+
+		}
+	}
+	return
+}
+
+func isPalindrome131(s string) bool {
+	slen := len(s)
+	for i, j := 0, slen-1; i < j; i, j = i+1, j-1 {
+		if s[i] != s[j] {
+			return false
+		}
+	}
+	return true
+}
+
+// 解法二
+func partition131_1(s string) [][]string {
+	result := [][]string{}
+	size := len(s)
+	if size == 0 {
+		return result
+	}
+	current := make([]string, 0, size)
+	dfs131(s, 0, current, &result)
+	return result
+}
+
+func dfs131(s string, idx int, cur []string, result *[][]string) {
+	start, end := idx, len(s)
+	if start == end {
+		temp := make([]string, len(cur))
+		copy(temp, cur)
+		*result = append(*result, temp)
+		return
+	}
+	for i := start; i < end; i++ {
+		if isPal(s, start, i) {
+			dfs131(s, i+1, append(cur, s[start:i+1]), result)
+		}
+	}
+}
+
+func isPal(str string, s, e int) bool {
+	for s < e {
+		if str[s] != str[e] {
+			return false
+		}
+		s++
+		e--
+	}
+	return true
+}
+
+```