public class Solution {
/**
*
* @param s string字符串
* @return bool布尔型
*/
public boolean isValid (String s) {
// write code here
Stack<Character> stack = new Stack();
for(int i = 0; i< s.length();i++){
char next = s.charAt(i);
if(next == '(' || next == '{' || next == '['){
stack.push(next);
} else {
if(stack.isEmpty()){
return false;
}
char pop = stack.pop();
if((pop == '(' && next != ')') || (pop == '{' && next != '}') || (pop == '[' && next != ']')){
return false;
}
}
}
if(stack.isEmpty()){
return true;
}
return false;
}
}