Valid Parentheses

class Solution {
public:
    bool isValid(string s) {
        stack<char> st;
        for (char c : s) {
            if (c == '(' || c == '[' || c == '{') st.push(c);
            else {
                if (st.empty()) return false;
                char t = st.top(); st.pop();
                if ((c == ')' && t != '(') ||
                    (c == ']' && t != '[') ||
                    (c == '}' && t != '{')) return false;
            }
        }
        return st.empty();
    }
};

func isValid(s string) bool {
    st := []byte{}
    for i := 0; i < len(s); i++ {
        c := s[i]
        if c == '(' || c == '[' || c == '{' {
            st = append(st, c)
        } else {
            if len(st) == 0 {
                return false
            }
            t := st[len(st)-1]
            st = st[:len(st)-1]
            if (c == ')' && t != '(') ||
                (c == ']' && t != '[') ||
                (c == '}' && t != '{') {
                return false
            }
        }
    }
    return len(st) == 0
}

class Solution:
    def isValid(self, s: str) -> bool:
        match = {')': '(', ']': '[', '}': '{'}
        st = []
        for c in s:
            if c in '([{':
                st.append(c)
            else:
                if not st or st[-1] != match[c]:
                    return False
                st.pop()
        return not st

function isValid(s) {
    const match = { ')': '(', ']': '[', '}': '{' };
    const st = [];
    for (const c of s) {
        if (c === '(' || c === '[' || c === '{') {
            st.push(c);
        } else {
            if (st.length === 0 || st[st.length - 1] !== match[c]) return false;
            st.pop();
        }
    }
    return st.length === 0;
}

class Solution {
    public boolean isValid(String s) {
        Deque<Character> st = new ArrayDeque<>();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '(' || c == '[' || c == '{') {
                st.push(c);
            } else {
                if (st.isEmpty()) return false;
                char t = st.pop();
                if ((c == ')' && t != '(') ||
                    (c == ']' && t != '[') ||
                    (c == '}' && t != '{')) return false;
            }
        }
        return st.isEmpty();
    }
}

function isValid(s: string): boolean {
    const match: Record<string, string> = { ')': '(', ']': '[', '}': '{' };
    const st: string[] = [];
    for (const c of s) {
        if (c === '(' || c === '[' || c === '{') {
            st.push(c);
        } else {
            if (st.length === 0 || st[st.length - 1] !== match[c]) return false;
            st.pop();
        }
    }
    return st.length === 0;
}