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

in java you don't want to compare the string or char by == signs. you would use equals method. equalsIgnoreCase or something of the like. if you use == it must point to the same memory location. In the method below I attempted to use ints to get around this. using ints here from the string index since every opening brace has a closing brace. I wanted to use location match instead of a comparison match. But i think with this you have to be intentional in where you place the characters of the string. Lets also consider that Yes = true and No = false for simplicity. This answer assumes that you passed an array of strings to inspect and required an array of if yes (they matched) or No (they didn't)

import java.util.Stack; 

    public static void main(String[] args) {

    //String[] arrayOfBraces = new String[]{"{[]}","([{}])","{}{()}","{}","}]{}","{[)]()}"};
    // Example: "()" is balanced
    // Example: "{ ]" is not balanced.
    // Examples: "()[]{}" is balanced.
    // "{([])}" is balanced
    // "{([)]}" is _not_ balanced

    String[] arrayOfBraces  = new String[]{"{[]}","([{}])","{}{()}","()[]{}","}]{}","{[)]()}","{[)]()}","{([)]}"};
    String[] answers        = new String[arrayOfBraces.length];     
    String openers          = "([{";
    String closers          = ")]}";
    String stringToInspect  = ""; 
    Stack stack     = new Stack();


    for (int i = 0; i < arrayOfBraces.length; i++) {

        stringToInspect = arrayOfBraces[i];
        for (int j = 0; j < stringToInspect.length(); j++) {            
            if(stack.isEmpty()){
                if (openers.indexOf(stringToInspect.charAt(j))>=0) {
                    stack.push(""+stringToInspect.charAt(j));   
                }
                else{
                    answers[i]= "NO";
                    j=stringToInspect.length();
                }                   
            }
            else if(openers.indexOf(stringToInspect.charAt(j))>=0){
                stack.push(""+stringToInspect.charAt(j));   
            }
            else{
                String comparator = stack.pop();
                int compLoc = openers.indexOf(comparator);
                int thisLoc = closers.indexOf(stringToInspect.charAt(j));

                if (compLoc != thisLoc) {
                    answers[i]= "NO";
                    j=stringToInspect.length();                     
                }
                else{
                    if(stack.empty() && (j== stringToInspect.length()-1)){
                        answers[i]= "YES";
                    }
                }
            }
        }
    }

    System.out.println(answers.length);         
    for (int j = 0; j < answers.length; j++) {
        System.out.println(answers[j]);
    }       
}