【leetcode】20. 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.
*/
#include <iostream>
#include <string>
#include <vector>
#include <stack>

using namespace std;

bool isValid(string s)
{
stack<char> char_stack;

for (int i = 0; i < s.length(); i++)
{
if (s[i] == '(' || s[i] == '{' || s[i] == '[')
{
char_stack.push(s[i]);
}
else if (s[i] == ')' || s[i] == '}' || s[i] == ']')
{
if (s[i] == ')' && char_stack.top() == '(')
{
char_stack.pop();
}
else if (s[i] == '}' && char_stack.top() == '{')
{
char_stack.pop();
}
else if (s[i] == ']' && char_stack.top() == '[')
{
char_stack.pop();
}
else
{
return false;
}
}
else
continue;
}
return char_stack.empty();
}

int main()
{
string str = "([)]";

cout << isValid(str);
system("pause");
return 0;
}