Update 0020.有效的括号.md

problems/0020.有效的括号.md

@@ -157,7 +157,26 @@ class Solution:
 ```
 
 Go：
+```Go
+func isValid(s string) bool {
+    hash := map[byte]byte{')':'(', ']':'[', '}':'{'}
+    stack := make([]byte, 0)
+    if s == "" {
+        return true
+    }
 
+    for i := 0; i < len(s); i++ {
+        if s[i] == '(' || s[i] == '[' || s[i] == '{' {
+            stack = append(stack, s[i])
+        } else if len(stack) > 0 && stack[len(stack)-1] == hash[s[i]] {
+            stack = stack[:len(stack)-1]
+        } else {
+            return false
+        }
+    }
+    return len(stack) == 0
+}
+```