LeetCode_20---Valid Parentheses

Given a string containing just the characters 

'('

, 

')'

, 

'{'

, 

'}'

, 

'['

 and 

']'

,
determine if the input string is valid.
The brackets must close in the correct order, 

"()"

 and 

"()[]{}"

 are
all valid but 

"(]"

 and 

"([)]"

 are
not.
翻译：

Code:

import java.util.HashMap;
import java.util.Stack;

/**
* @author MohnSnow
* @time 2015年6月5日 下午3:36:49
*
*/
public class LeetCode20 {

/**
* @param argsmengdx
* -fnst
*/
//288msA---没有前五行的时候316ms
public static boolean isValid(String s) {
int len = s.length();
if (len == 0)
return true;
if (len % 2 != 0)
return false;
HashMap<Character, Character> map = new HashMap<Character, Character>();
map.put('(', ')');
map.put('[', ']');
map.put('{', '}');
System.out.println(map.keySet().toString());
Stack<Character> stack = new Stack<Character>();
for (int i = 0; i < s.length(); i++) {
char curr = s.charAt(i);
if (map.keySet().contains(curr)) {
stack.push(curr);
} else if (map.values().contains(curr)) {
if (!stack.empty() && map.get(stack.peek()) == curr) {
stack.pop();
} else {
return false;
}
}
}
return stack.empty();
}

public static void main(String[] args) {
String s = "{}{}[][][]{}]}[{[()())()))(()";
System.out.println(isValid(s));
}
}