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 a 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.
map.put剩下的total_sum和index,求到这里来了
之后一直提取if (k != 0) total_sum %= k;
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
class Solution { public boolean checkSubarraySum(int[] nums, int k) { //cc if (nums == null || nums.length == 0) return false; //ini: map Map<Integer, Integer> map = new HashMap<Integer, Integer>(){{put(0,-1);}};; int total_sum = 0; //for loop: get the same sum for (int i = 0; i < nums.length; i++) { total_sum += nums[i]; if (k != 0) total_sum %= k; Integer pos = map.get(total_sum); if (pos != null) { if (i - pos > 1) return true; }else { map.put(total_sum, i); } } return false; } }