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  • valid Parentheses

    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();
            }
    };
    怕什么真理无穷,进一寸有一寸的欢喜。---胡适
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  • 原文地址:https://www.cnblogs.com/hujianglang/p/11432190.html
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