Balanced Brackets

1. You are given a string exp representing an expression.

2. You are required to check if the expression is balanced i.e. closing brackets and opening brackets match up well.

e.g.

[(a + b) + {(c + d) * (e / f)}] -> true

[(a + b) + {(c + d) * (e / f)]} -> false

[(a + b) + {(c + d) * (e / f)} -> false

([(a + b) + {(c + d) * (e / f)}] -> false

Input Format

A string str

Output Format

true or false

Constraints

0 <= str.length <= 100

Sample Input

[(a + b) + {(c + d) * (e / f)}]

Sample Output

true

Solution

import java.io.*;

import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {

        Scanner sc = new Scanner(System.in);

        String str = sc.nextLine();

        int n = str.length();

        Stack<Character> s = new Stack<>();

        for(int i=0;i<n;i++){

            char ch = str.charAt(i);

            if(ch == '[')

                s.push(']');

            else if(ch == '{')

                s.push('}');

            else if(ch == '(')

                s.push(')');

            else if(ch == '}' || ch == ']' || ch == ')'){

                if(!s.empty() && s.peek() == ch)

                    s.pop();

                else{

                    System.out.println(false);

                    return;

                }

            }

        }

        if(s.empty())

            System.out.println(true);

        else 

            System.out.println(false);

    }

}