Leet Code Daily 2024-06-08 - Continuous Subarray Sum

class Solution {
public:
    bool checkSubarraySum(vector<int>& nums, int k) {
        vector<int> sums = {0};
        for (const auto& x : nums) {
            sums.push_back(sums.back() + x);
        }
        unordered_set<int> mods;
        for (int i = 0; i < sums.size(); i++) {
            if (i - 2 >= 0) {
                mods.insert(sums[i - 2] % k);
            }
            if (mods.contains(sums[i] % k)) {
                return true;
            }
        }
        return false;
    }
};