Subarray Sum Visualizer with Animation

560. Subarray Sum Equals K

Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals to k.

A subarray is a contiguous non-empty sequence of elements within an array.

Example 1:

Input: nums = [1, 1, 1], k = 2

Output: 2

Example 2:

Input: nums = [1, 2, 3], k = 3

Output: 2

Constraints:

• 1 <=n ums.length <=2 * 10⁴
• -1000 <=n ums[i] <=1 000
• -10⁷ <=k <=1 0⁷

Difficulty: Medium | Topics: Arrays, Hashmaps

Enter the array of integers and a target sum (k). The visualizer will show how many subarrays sum up to k.

Array (comma separated): Target Sum (k):

Java Code: Subarray Sum Equals K

class Solution {
    public int subarraySum(int[] nums, int k) {
        Map<Integer, Integer> map = new HashMap<>();
        map.put(0, 1);
        int count = 0;
        int sum = 0;

        for(int num : nums) {
            sum += num;
            int diff = sum - k;
            if(map.containsKey(diff)) {
                count += map.get(diff);
            }
            map.put(sum, map.getOrDefault(sum, 0) + 1);
        }

        return count;
    }
}