diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md
index 57aa5a01..ec49c1c9 100644
--- a/problems/0020.有效的括号.md
+++ b/problems/0020.有效的括号.md
@@ -284,5 +284,70 @@ var isValid = function(s) {
```
+Swift
+```swift
+func isValid(_ s: String) -> Bool {
+ var stack = [String.Element]()
+ for ch in s {
+ if ch == "(" {
+ stack.append(")")
+ } else if ch == "{" {
+ stack.append("}")
+ } else if ch == "[" {
+ stack.append("]")
+ } else {
+ let top = stack.last
+ if ch == top {
+ stack.removeLast()
+ } else {
+ return false
+ }
+ }
+ }
+ return stack.isEmpty
+}
+```
+
+C:
+```C
+//辅助函数：判断栈顶元素与输入的括号是否为一对。若不是，则返回False
+int notMatch(char par, char* stack, int stackTop) {
+ switch(par) {
+ case ']':
+ return stack[stackTop - 1] != '[';
+ case ')':
+ return stack[stackTop - 1] != '(';
+ case '}':
+ return stack[stackTop - 1] != '{';
+ }
+ return 0;
+}
+
+bool isValid(char * s){
+ int strLen = strlen(s);
+ //开辟栈空间
+ char stack[5000];
+ int stackTop = 0;
+
+ //遍历字符串
+ int i;
+ for(i = 0; i < strLen; i++) {
+ //取出当前下标所对应字符
+ char tempChar = s[i];
+ //若当前字符为左括号，则入栈
+ if(tempChar == '(' || tempChar == '[' || tempChar == '{')
+ stack[stackTop++] = tempChar;
+ //若当前字符为右括号，且栈中无元素或右括号与栈顶元素不符，返回False
+ else if(stackTop == 0 || notMatch(tempChar, stack, stackTop))
+ return 0;
+ //当前字符与栈顶元素为一对括号，将栈顶元素出栈
+ else
+ stackTop--;
+ }
+ //若栈中有元素，返回False。若没有元素（stackTop为0），返回True
+ return !stackTop;
+}
+```
+
-----------------------
diff --git a/problems/0131.分割回文串.md b/problems/0131.分割回文串.md
index f674835d..075734ea 100644
--- a/problems/0131.分割回文串.md
+++ b/problems/0131.分割回文串.md
@@ -450,6 +450,101 @@ var partition = function(s) {
};
```
+##C
+```c
+char** path;
+int pathTop;
+char*** ans;
+int ansTop = 0;
+int* ansSize;
+
+//将path中的字符串全部复制到ans中
+void copy() {
+ //创建一个临时tempPath保存path中的字符串
+ char** tempPath = (char**)malloc(sizeof(char*) * pathTop);
+ int i;
+ for(i = 0; i < pathTop; i++) {
+ tempPath[i] = path[i];
+ }
+ //保存tempPath
+ ans[ansTop] = tempPath;
+ //将当前path的长度（pathTop）保存在ansSize中
+ ansSize[ansTop++] = pathTop;
+}
+
+//判断字符串是否为回文字符串
+bool isPalindrome(char* str, int startIndex, int endIndex) {
+ //双指针法：当endIndex（右指针）的值比startIndex（左指针）大时进行遍历
+ while(endIndex >= startIndex) {
+ //若左指针和右指针指向元素不一样，返回False
+ if(str[endIndex--] != str[startIndex++])
+ return 0;
+ }
+ return 1;
+}
+
+//切割从startIndex到endIndex子字符串
+char* cutString(char* str, int startIndex, int endIndex) {
+ //开辟字符串的空间
+ char* tempString = (char*)malloc(sizeof(char) * (endIndex - startIndex + 2));
+ int i;
+ int index = 0;
+ //复制子字符串
+ for(i = startIndex; i <= endIndex; i++)
+ tempString[index++] = str[i];
+ //用'\0'作为字符串结尾
+ tempString[index] = '\0';
+ return tempString;
+}
+
+void backTracking(char* str, int strLen, int startIndex) {
+ if(startIndex >= strLen) {
+ //将path拷贝到ans中
+ copy();
+ return ;
+ }
+
+ int i;
+ for(i = startIndex; i < strLen; i++) {
+ //若从subString到i的子串是回文字符串，将其放入path中
+ if(isPalindrome(str, startIndex, i)) {
+ path[pathTop++] = cutString(str, startIndex, i);
+ }
+ //若从startIndex到i的子串不为回文字符串，跳过这一层
+ else {
+ continue;
+ }
+ //递归判断下一层
+ backTracking(str, strLen, i + 1);
+ //回溯，将path中最后一位元素弹出
+ pathTop--;
+ }
+}
+
+char*** partition(char* s, int* returnSize, int** returnColumnSizes){
+ int strLen = strlen(s);
+ //因为path中的字符串最多为strLen个（即单个字符的回文字符串），所以开辟strLen个char*空间
+ path = (char**)malloc(sizeof(char*) * strLen);
+ //存放path中的数组结果
+ ans = (char***)malloc(sizeof(char**) * 40000);
+ //存放ans数组中每一个char**数组的长度
+ ansSize = (int*)malloc(sizeof(int) * 40000);
+ ansTop = pathTop = 0;
+
+ //回溯函数
+ backTracking(s, strLen, 0);
+
+ //将ansTop设置为ans数组的长度
+ *returnSize = ansTop;
+ //设置ans数组中每一个数组的长度
+ *returnColumnSizes = (int*)malloc(sizeof(int) * ansTop);
+ int i;
+ for(i = 0; i < ansTop; ++i) {
+ (*returnColumnSizes)[i] = ansSize[i];
+ }
+ return ans;
+}
+```
-----------------------
diff --git a/problems/0654.最大二叉树.md b/problems/0654.最大二叉树.md
index af945aca..361a92d1 100644
--- a/problems/0654.最大二叉树.md
+++ b/problems/0654.最大二叉树.md
@@ -256,6 +256,23 @@ class Solution {
## Python
```python
+class Solution:
+ """递归法 更快"""
+ def constructMaximumBinaryTree(self, nums: List[int]) -> TreeNode:
+ if not nums:
+ return None
+ maxvalue = max(nums)
+ index = nums.index(maxvalue)
+
+ root = TreeNode(maxvalue)
+
+ left = nums[:index]
+ right = nums[index + 1:]
+
+ root.left = self.constructMaximumBinaryTree(left)
+ root.right = self.constructMaximumBinaryTree(right)
+ return root
+
class Solution:
"""最大二叉树 递归法"""
diff --git a/problems/1047.删除字符串中的所有相邻重复项.md b/problems/1047.删除字符串中的所有相邻重复项.md
index 66f34978..e43ab59f 100644
--- a/problems/1047.删除字符串中的所有相邻重复项.md
+++ b/problems/1047.删除字符串中的所有相邻重复项.md
@@ -319,6 +319,22 @@ char * removeDuplicates(char * s){
}
```
+Swift：
+```swift
+func removeDuplicates(_ s: String) -> String {
+ let array = Array(s)
+ var stack = [Character]()
+ for c in array {
+ let last: Character? = stack.last
+ if stack.isEmpty || last != c {
+ stack.append(c)
+ } else {
+ stack.removeLast()
+ }
+ }
+ return String(stack)
+}
+```
-----------------------
