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Код

public class BraceCheckerProblem {

    public class Stack {

        private final int TOP;
        private final int BOTTOM = 0;

        private char[] stack;
        private int sp = BOTTOM;

        public Stack(int size) {
            TOP = size;
            stack = new char[TOP];
        }

        public void push(char c) {
            if (sp < TOP) {
                stack[sp++] = c;
            }
        }

        public char pop() {
            char val = 0;
            if (sp > BOTTOM) {
                val = stack[--sp];
            }

            return val;
        }
    }

    private String inputText;
    private String ErrorMessage1 = " <--\nIncorect brace";
    private String ErrorMessage2 = " <--\nStack bottom reached while parsing";
    private String ErrorMessage3 = " <--\nStack not empty at string end";
    private String GoodMessage = "\nOK";

    private Stack stack;

    public BraceCheckerProblem(String inputStr) {
        this.inputText = inputStr;
        stack = new Stack(inputStr.length());
    }

    public void parse() {
        char spop = 0;

        for (int i = 0; i < inputText.length(); i++) {
            char ch = inputText.charAt(i);
            System.out.print(ch);
            switch (ch) {
            case '[':
                stack.push('[');
                break;
            case '{':
                stack.push('{');
                break;
            case '(':
                stack.push('(');
                break;
            // TODO: push , after which break;
            case ']':
                spop = stack.pop();
                if (spop != '[') {
                    System.out.println(ErrorMessage1);
                    return;
                } else if (spop == 0) {
                    System.out.println(ErrorMessage2);
                }
                break;
            case '}':
                spop = stack.pop();
                if (spop != '{') {
                    System.out.println(ErrorMessage1);
                    return;
                } else if (spop == 0) {
                    System.out.println(ErrorMessage2);
                }
                break;
            case ')':
                spop = stack.pop();
                if (spop != '(') {
                    System.out.println(ErrorMessage1);
                    return;
                } else if (spop == 0) {
                    System.out.println(ErrorMessage2);
                }
                break;
            }
        }

        spop = stack.pop();
        if (spop > 0) {
            System.out.println(ErrorMessage3);
        }

        System.out.println(GoodMessage);
    }

    public static void main(String[] args) {
        String str = "({{[]}})({}){{hgh}{()}}}";

        BraceCheckerProblem bcp = new BraceCheckerProblem(str);
        bcp.parse();
    }

}