20. Valid Parentheses

bool isValid(string s) {
stack<char> temp;
map<char, char> m = { {']','['},{')','('},{'}','{'} };
for (int i = 0; i < s.size(); i++) {
if (s[i] == '[' || s[i] == '(' || s[i] == '{')
temp.push(s[i]);
else if (s[i] == ']' || s[i] == ')' || s[i] == '}')
{
if (temp.empty()||temp.top() != m[s[i]]) return false;
else temp.pop();
}
}
return temp.empty();
}