Continuous Subarray Sum

class Solution {
    public boolean checkSubarraySum(int[] nums, int k) {
        boolean a = false;
        if(k==0){
            a = true;
        }
        int[] runningSums = new int[nums.length+1];
        for(int i = 0; i<nums.length; i++){
            runningSums[i+1] = nums[i] + runningSums[i];
        }
        
        for(int i = 0; i<runningSums.length; i++){
            for(int j = runningSums.length-1; j>i+1; j--){
                if(a){
                    if((runningSums[j] - runningSums[i]) == 0){
                        return true;
                    }
                }
                else{
                    if((runningSums[j] - runningSums[i]) % k == 0){
                        return true;
                    }
                }
            }
        }
        return false;
    }
}