Find subarrays with given sum in an array.

ghz 10months ago ⋅ 89 views

To find subarrays with a given sum in an array, you can use a sliding window approach. Here's a Java implementation:

import java.util.ArrayList;
import java.util.List;

public class SubarraysWithGivenSum {

    public static List<List<Integer>> findSubarrays(int[] nums, int targetSum) {
        List<List<Integer>> result = new ArrayList<>();
        int n = nums.length;
        int sum = 0;
        int left = 0;

        for (int right = 0; right < n; right++) {
            sum += nums[right];

            while (sum > targetSum && left <= right) {
                sum -= nums[left++];
            }

            if (sum == targetSum) {
                List<Integer> subarray = new ArrayList<>();
                for (int i = left; i <= right; i++) {
                    subarray.add(nums[i]);
                }
                result.add(subarray);
            }
        }

        return result;
    }

    public static void main(String[] args) {
        int[] nums = {1, 4, 20, 3, 10, 5};
        int targetSum = 33;
        List<List<Integer>> subarrays = findSubarrays(nums, targetSum);

        System.out.println("Subarrays with sum " + targetSum + ":");
        for (List<Integer> subarray : subarrays) {
            System.out.println(subarray);
        }
    }
}

In this implementation:

  • We use a sliding window to find subarrays with the given sum.
  • We maintain two pointers, left and right, to define the current window.
  • We continuously expand the window by moving the right pointer until the sum of elements in the window exceeds the target sum.
  • If the sum of the current window equals the target sum, we add the subarray defined by the window to the result list.
  • We continue this process until we reach the end of the array.
  • We test the implementation with an example array and target sum and print the subarrays with the given sum.
#algorithm