diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md
index 57aa5a01..6c6f0cb7 100644
--- a/problems/0020.有效的括号.md
+++ b/problems/0020.有效的括号.md
@@ -283,6 +283,47 @@ var isValid = function(s) {
 };
 ```
 
+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;
+}
+```
+
 
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