Parenthesis/Brackets Matching using Stack algorithm

Question

For example if the parenthesis/brackets is matching in the following:

({})
(()){}()
()

and so on but if the parenthesis/brackets is not mat

Answer 1

You're doing some extra checks that aren't needed. Doesn't make any diff to functionality, but a cleaner way to write your code would be:

public static boolean isParenthesisMatch(String str) {
    Stack stack = new Stack();
    char c;

    for (int i = 0; i < str.length(); i++) {
        c = str.charAt(i);
        if (c == '(' || c == '{')
            stack.push(c);
        else if (stack.empty())
            return false;
        else if (c == ')') {
            if (stack.pop() != '(')
                return false;
        } else if (c == '}') {
            if (stack.pop() != '{')
                return false;
        }
    }
    return stack.empty();
}

There is no reason to peek at a paranthesis before removing it from the stack. I'd also consider wrapping instruction blocks in parantheses to improve readability.