LeetCode


题目:

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.

思路:

用栈来解决。

package ds;

import java.util.Stack;

public class ValidParentheses {

public boolean isValid(String s) {
Stack
<Character> stack = new Stack<Character>();
int len = s.length();
for (int i = 0; i < len; ++i) {
char c = s.charAt(i);
switch (c) {
case '(':

case '[':

case '{':
stack.push(c);
break;
case ')':
if (stack.isEmpty() || stack.pop() != '(')
return false;
break;
case ']':
if (stack.isEmpty() || stack.pop() != '[')
return false;
break;
case '}':
if (stack.isEmpty() || stack.pop() != '{')
return false;
break;
}
}

return stack.isEmpty();
}

public static void main(String[] args) {
// TODO Auto-generated method stub
ValidParentheses v = new ValidParentheses();
// Test case 1
System.out.println(v.isValid("()[]}"));
// Test case 2
System.out.println(v.isValid("("));
}

}

 

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本文转载自:http://www.cnblogs.com/shuaiwhu/p/5060243.html     作者:Valid Parentheses - NULL00     发布日期:2015/12/20     本站转载的文章为个人学习借鉴使用,本站对版权不负任何法律责任。如果侵犯了您的隐私权益,请联系我们删除。


 
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