Valid Parentheses

来源：互联网发布：java互联网必读编辑：程序博客网时间：2024/06/07 11:18

问题描述

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.

解决方案

class Solution {public:    bool popAndTest( stack<char> &chStack, char ch ) {        if( chStack.empty() ) {            return false;        }        char top = chStack.top();        chStack.pop();        if( top != ch ) {            return false;        } else {            return true;        }    }    bool isValid(string s) {        if( s.size() % 2 != 0 ) {            return false;        }                stack<char> charStack;        for( auto ch : s ) {            if( ch == ')' ) {                if( !popAndTest(charStack, '(') ) {                    return false;                }            }            else if( ch == ']' ) {                if( !popAndTest(charStack, '[') ) {                    return false;                }            }            else if( ch == '}' ) {                if( !popAndTest(charStack, '{') ) {                    return false;                }            } else {                charStack.push( ch );            }        }                if( !charStack.empty() ) {            return false;        } else {            return true;           }    }};

0 0