gistfile0.txt

class Solution {
public:
    int numberOfArithmeticSlices(vector<int>& nums) {
        int out = 0;
        int s = 0;
        while (s + 1 < nums.size()) {
            int dif = nums[s + 1] - nums[s];
            int e = s + 2;
            while (e < nums.size() && nums[e] - nums[e - 1] == dif) {
                ++e;
            }
            int len = e - s;
            // count
            out += (len - 2) * (len - 1) / 2;

            s = e - 1;
        }
        return out;
    }
};