Leetcode-Solutions/20-valid-parentheses.cpp at main · aghersidev/Leetcode-Solutions · GitHub

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class Solution {
public:
    bool isValid(string s) {
        stack<char> chars;
        for (int i = 0; i < s.length(); i++) {
            if (s[i] == '(' || s[i] == '{' || s[i] == '[') {
                chars.push(s[i]);
            };
            if (s[i] == ')') {
                if (chars.empty())
                    return false;

                if (chars.top() == '(') {
                    chars.pop();
                } else
                    return false;
            };
            if (s[i] == '}') {
                if (chars.empty())
                    return false;
                if (chars.top() == '{') {
                    chars.pop();
                } else
                    return false;
            };
            if (s[i] == ']') {
                if (chars.empty())
                    return false;
                if (chars.top() == '[') {
                    chars.pop();
                } else
                    return false;
            };
        }
        if (chars.size() != 0)
            return false;
        return true;
    }
};