最长连续匹配括号数

Author: tanglu

LongestValidParentheses.java

@@ -0,0 +1,28 @@
+public class Solution {
+    public int longestValidParentheses(String s) {
+        if(s==null||s.length()==0) {
+            return 0;
+        }
+        int start     = -1;
+        int maxLength = 0;
+        Stack stack   = new Stack();
+        for(int i=0;i<s.length();i++) {
+            if(s.charAt(i)=='(') {
+                stack.push(i);
+            } else {
+                if(!stack.empty()) {
+                    stack.pop();
+                    if(stack.empty()==true) {
+                        maxLength = Math.max(i - start , maxLength);
+                    } else {
+                        maxLength = Math.max(i - (int)stack.peek() , maxLength);
+                    }
+                } else {
+                    start = i;
+                }
+            }
+        }
+    
+        return maxLength;
+    }
+}