LeetCode - Continuous Subarray Sum

Question Definition

Given a list of non-negative numbers and a target integer k, write a function to check if the array has a continuous subarray of size at least 2 that sums up to the multiple of k, that is, sums up to n*k where n is also an integer. Example 1:

Input: [23, 2, 4, 6, 7],  k=6
Output: True
Explanation: Because [2, 4] is a continuous subarray of size 2 and sums up to 6.

Example 2:

Input: [23, 2, 6, 4, 7],  k=6
Output: True
Explanation: Because [23, 2, 6, 4, 7] is an continuous subarray of size 5 and sums up to 42.

Note:

1. The length of the array won’t exceed 10,000.
2. You may assume the sum of all the numbers is in the range of a signed 32-bit integer.

   Java Solution

   public boolean checkSubarraySum(int[] nums, int k) {
    int[] sum = new int[nums.length + 1];
    sum[0] = 0;
    for(int i = 1; i <= nums.length; i++)
        sum[i] = nums[i - 1] + sum[i - 1];
    for(int i = 0; i < nums.length; i++){
        for(int j = i + 2; j <= nums.length; j++){
            if (sum[j] - sum[i] == k) return true;
            if (k != 0 && ((sum[j] - sum[i]) % k == 0)) return true;
        }
    }
    return false;
   }