﻿ Java - Find the equilibrium indices from an array of integers

# Java: Find the equilibrium indices from a given array of integers

## Java Array: Exercise-62 with Solution

Write a Java program to find equilibrium indices in a given array of integers.

An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.

```For example, in a sequence A:
A0 = -7
A1 = 1
A2 = 5
A3 = 2
A4 = -4
A5 = 3
A6 = 0
3 is an equilibrium index, because:

A0 + A1 + A2 = A4 + A5 + A6

6 is also an equilibrium index, because:

A0 + A1 + A2 + A3 + A4 + A5 = 0

(sum of zero elements is zero)

7 is not an equilibrium index, because it is not a valid index of sequence A.```

Example:
Input :
nums = {-7, 1, 5, 2, -4, 3, 0}
Output:
Equilibrium indices found at : 3
Equilibrium indices found at : 6
Source: https://bit.ly/2ziUROQ

Sample Solution:

Java Code:

``````//Source: https://bit.ly/2ziUROQ

// Import the necessary Java class.
import java.util.Arrays;

// Define a class named 'solution'.
public class solution {
public static void main(String[] args) {
// Initialize an array of integers.
int[] nums = {-7, 1, 5, 2, -4, 3, 0};
System.out.println("Original array: " + Arrays.toString(nums));

// Call the 'equlibrium_indices' method to find equilibrium indices.
equlibrium_indices(nums);
}

public static void equlibrium_indices(int[] nums) {
// Find the total sum of elements in the array.
int totalSum = 0;
for (int n : nums) {
totalSum += n;
}

// Initialize a running sum to keep track of the sum as we iterate.
int runningSum = 0;

// Iterate through the array to find equilibrium indices.
for (int i = 0; i < nums.length; i++) {
int n = nums[i];

// Check if the current index is an equilibrium index.
if (totalSum - runningSum - n == runningSum) {
System.out.println("Equilibrium indices found at: " + i);
}

// Update the running sum as we move through the array.
runningSum += n;
}
}
}
```
```

Sample Output:

```Original array: [-7, 1, 5, 2, -4, 3, 0]
Equilibrium indices found at : 3
Equilibrium indices found at : 6
```

Flowchart:

Java Code Editor:

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