logo
  • Programming
  • Testing
  • AI
  • Devops
  • Data Science
  • Design
  • Blog
  • Crypto Tools
  • Dev Feed
  • Login
Story
Follow @devglan

Java Program to Find middle index of array where both ends sum is equal

author-image   By Dhiraj Ray,   01 January, 2018 16K

Description

In the java interview, you will be asked to find the middle index or position of a given array where sum of numbers preceding the index is equals to sum of numbers succeeding the index.There are two ways to solve this problem.One is to use 2 for loops - one starting from the last index to the middle index and another starting from start index to middle index. Another way to solve it by using while loop - the while loop should stop when the start index crosses the end index. Following is the program to achieve this using while loop.

FindMiddleIndex.java
package com.devglan;

public class FindMiddleIndex {

    public static int findMiddleIndex(int[] array) throws Exception {

        int endIndex = array.length - 1;
        int startIndex = 0;
        int leftSum = 0;
        int rightSum = 0;
        while (true) {
            if (leftSum > rightSum) {
                rightSum += array[endIndex--];
            } else {
                leftSum += array[startIndex++];
            }
            if (startIndex > endIndex) {
                if (leftSum == rightSum) {
                    break;
                } else {
                    throw new Exception(
                            "No such combination found in the array.");
                }
            }
        }
        return endIndex;
    }

    public static void main(String[] args) {
        int[] array = {1,7,5,2,8,3 };
        try {
            int index = findMiddleIndex(array);
            System.out.println("Sum preceding the index " + index + " is equal to sum succeeding the index " + index);
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
        }
    }
}

Explanation

Click to Suggest Your Own Explanation

Take two pointers, one starting from 0th index and another starting from array&aposs length-1 and start finding the sum from both ends.The point where these pointers crosses each other is the middle index or position of the array.Hence find the sum and conclude.

Other Similar Java Programs:

1 Java Program to test if given number is Armstrong or not
2 Java Program to test if a given number is Fibonacci or not
3 java program to find distinct word list from a file
4 Java program to find duplicate character from a string
5 Java Program to find line with max character length in descending order in Java
6 Java Program to find max two numbers in an array
7 Java program to find max repeated words from a file
8 Java program to find sum of prime numbers
9 Java program to reverse a given number
10 Java program to find permutations of a given string
11 Java program to reverse a given string
12 Java program to find factorial of a given number
13 Java Program for Binary Search
14 Java Program to Add Two 2D Matrix
15 3 Ways to Check if Given Words are Anagram or not
16 Java Program to Find LCM of a Two Given Number
17 Check Given String is Rotation of Another String
18 Java Program To Check If A Given Number is A Perfect Number
19 Remove Common Characters From Given Strings
20 Find Second Largest Number in Array
21 Java Program To Find the Longest Palindrome Present in a String
22 Java Program to Reverse an Array in Place Without Using Any Second Array
23 Java Program to Print 1 To 10 Without Using Loop
24 Write a Java Program to Compare Files in Java
25 Java Program to Find missing Number in an Array
26 Java Program to Find First non Repeated Character in a String
27 Write a Java Program to Find Union and Intersection of Arrays in Java
28 Writing a Java program to rotate an array by d elements.
29 Write a Java program to rotate a matrix
30 Write a Java program to find the largest sum of the contiguous subarray in a given Array

If You Appreciate This, You Can Consider:

  • Like us at: Facebook or follow us at Twitter
  • Share this article on social media or with your teammates.

Suggest Explanation

The suggestion has been saved for review.Thanks for your effort.

{{errorMessage}}

Vertex

Devglan is one stop platform for all
programming tutorials and courses.

About Us

  • About Us
  • Contact Us
  • Submission Criteria
  • Privacy Policy

Quick Links

  • Home
  • Login / Join
  • Submit Your Story
  • Donate

Contact Us

Dhiraj
dhiraj@devglan.com

© 2020 Devglan. All rights reserved.