Valid Parentheses LeetCode java

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.

三种括号组成的字符串，进行有效性判断，用普通的方法进行遍历比较，费事不说，种类的变化也不胜枚举。

这里，我们用了stack的特性，来进行比较。为（，【，｛则直接入栈，为）】｝则从stack弹出顶部的元素进行比较。

代码如下
public class Solution {
public boolean isValid(String s) {
Stack<Character> stack = new Stack<>();

char[] c = s.toCharArray();

for(int i = 0; i<c.length;i++){
if(c[i] == '(' || c[i] == '[' || c[i] == '{'){
stack.push(c[i]);
}else if(c[i] == ')' || c[i] == ']' ||c[i] == '}'){
if(stack.empty()){
return false;
}else{
char ch = stack.pop();
if( ch == '(' && c[i] == ')')continue;
if( ch == '[' && c[i] == ']')continue;
if( ch == '{' && c[i] == '}')continue;
else return false;
}
}
}
if(stack.empty()) return true;
else return false;
}
}



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