【leetcode】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.

【My Solution:】

#include "stdafx.h"
#include <iostream>
#include <vector>

using namespace std;

class Solution {
public:
bool checkMatch(char first,char second){
bool isMatch = false;
if((first == '(' && second == ')')
|| (first == '[' && second == ']')
|| (first == '{' && second == '}'))
{
isMatch = true;
}
return isMatch;
}

bool isValid(string s) {
bool isValid = false;
vector<char> vTemp;
if(s.length() <= 0){
return isValid;
}
//vTemp.push_back(s[0]);
for(int i = 0; i < s.length(); i++){
if(vTemp.size() == 0){
vTemp.push_back(s[i]);
}else{
vector<char>::iterator id = vTemp.end()-1;
if(checkMatch((*id),s[i])){
vTemp.erase(id);
}else{
vTemp.push_back(s[i]);
}
}
}
if(vTemp.size() == 0){
isValid = true;
}
return isValid;
}
};

int main(){
Solution solution;
solution.isValid("()");
solution.isValid("()[]{}");
solution.isValid("([)]");
return 0;
}

【other's】算法使用相同，都使用栈来实现，但his更简洁，1、直接用到了已有的数据结构stack；2、匹配用到了ASCII码，但这样不合适，万一输入为“sdsf”等字符，则结果不正确。

public class Solution {
public boolean isValid(String s) {
char [] arr = s.toCharArray();
Stack stack = new Stack();
for(char ch : arr){
if(stack.isEmpty()){
stack.push(ch);
}else{
char top = (char)stack.lastElement();
if(ch - top == 1 || ch - top == 2){
stack.pop();
}else{
stack.push(ch);
}
}
}
if(stack.isEmpty()){
return true;
}
return false;
}