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.
bool isValid(string s) { stack<char> st; for(char c : s) { if(!st.empty() && (c-st.top() == 1 || c-st.top() == 2)) { st.pop(); // )-(=1, ]-[=2, }-{=2 } else { st.push(c); } } return st.empty(); }