Leetcode problem 20. 'Valid Parentheses'

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import java.util.Scanner;
public class Main {
    public static boolean isValid(String s) {
        int parentheses = 0, curlyBraces = 0, squareBrackets = 0;
        for (char ch : s.toCharArray()) {
            if (ch == '(') parentheses++;
            else if (ch == ')') {
                parentheses--;
                if (parentheses < 0) return false;
            } else if (ch == '{') curlyBraces++;
            else if (ch == '}') {
                curlyBraces--;
                if (curlyBraces < 0) return false;
            } else if (ch == '[') squareBrackets++;
            else if (ch == ']') {
                squareBrackets--;
                if (squareBrackets < 0) return false;
            }
        }
        return parentheses == 0 && curlyBraces == 0 && squareBrackets == 0;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter a string:");
        String s = sc.nextLine();
        System.out.println(isValid(s) ? "Valid" : "Invalid");
        sc.close();
    }
}
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