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.
1 class Solution { 2 public: 3 bool checkSubarraySum(vector<int>& nums, int k) { 4 int n=nums.size(),pre=0,sum=0; 5 unordered_set<int>mod_k; 6 for(int i=0;i<n;i++) 7 { 8 sum+=nums[i]; 9 int mod=k==0?sum:sum%k; 10 if(mod_k.count(mod)) 11 return true; 12 mod_k.insert(pre); 13 pre=mod; 14 } 15 return false; 16 } 17 };
原文：http://www.cnblogs.com/KRCheung/p/6821328.html