﻿ Java - Index of the first and the last number of a subarray

# Java: Get the index of the first number and the last number of a subarray

## Java Basic: Exercise-139 with Solution

Write a Java program to get the index of the first and the last number of a subarray where the sum of numbers is zero. This is from a given array of integers.

Pictorial Presentation:

Sample Solution:

Java Code:

``````import java.util.*;

public class Solution {
// Function to find the subarray with a sum of zero in the given array
public static List<Integer> subarraySum(int[] nums) {
List<Integer> temp = new ArrayList<>();

// Check if the input array is null or empty, and return an empty list if so
if (nums == null || nums.length == 0) {
return temp;
}

int pre_Sum = 0;
Map<Integer, Integer> map = new HashMap<>();
map.put(pre_Sum, -1);

// Iterate through the elements of the input array
for (int i = 0; i < nums.length; i++) {
pre_Sum += nums[i];

// Check if the current prefix sum already exists in the map
if (map.containsKey(pre_Sum)) {
temp.add(map.get(pre_Sum) + 1); // Add the start index of the subarray
temp.add(i); // Add the end index of the subarray
return temp; // Return the list of indices
}

// If the prefix sum is not found, add it to the map with its index
map.put(pre_Sum, i);
}

return temp; // Return an empty list if no subarray with a sum of zero is found
}

public static void main(String[] args) {
int[] nums = {1, 2, 3, -6, 5, 4};

// Print the original array and the indices of the subarray with a sum of zero
System.out.println("Original Array: " + Arrays.toString(nums));
System.out.println("Index of the subarray of the said array where the sum of numbers is zero: " + subarraySum(nums));
}
}
```
```

Sample Output:

```Original Array : [1, 2, 3, -6, 5, 4]
Index of the subarray of the said array where the sum of numbers is zero: [0, 3]
```

Flowchart:

Java Code Editor:

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