Given a string containing just the characters ‘(’, ‘)’, ‘{’, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order. Note that an empty string is also considered valid.
Example 1:
Input: “()” Output: true Example 2:
Input: “()[]{}” Output: true Example 3:
Input: “(]” Output: false Example 4:
Input: “([)]” Output: false Example 5:
Input: “{[]}” Output: true
class Solution{ public: bool isValid(string const& s){ string left = "([{"; string right = ")]}"; stack<char> stk; for(auto c:s){ if(left.find(c) != string::npos){ stk.push(c); } else{ if(stk.empty() || stk.top() != left[right.find(c)]) return false; else stk.pop(); } } return stk.empty(); } };
原文：https://www.cnblogs.com/hujianglang/p/11432190.html