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.
class Solution { public: bool match(char a, char b) { if (a == '[' && b == ']') return true; if (a == '(' && b == ')') return true; if (a == '{' && b == '}') return true; return false; } bool isValid(string s) { int len = s.size(); if (len % 2 == 1) return false; stack<char> r; int i = 0; r.push(s[i++]); while (i < len) { if (r.empty()) { r.push(s[i++]); continue; } if (match(r.top(), s[i])) { r.pop(); i++; } else { r.push(s[i++]); } } if (r.empty()) return true; else return false; } };