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class Solution {
public:
    int arithmeticTriplets(vector<int>& nums, int diff) {
        cin.tie(nullptr)->sync_with_stdio(0);

        unordered_set<int> mp(nums.begin(), nums.end());
        int ans = 0;
        for (int it : nums) {

            if (mp.count(it - diff) && mp.count(it + diff)) {
                ans += 1;
            }
        }
        return ans;
    }
};
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class Solution {
public:
    int arithmeticTriplets(vector<int>& nums, int diff) {
        cin.tie(nullptr)->sync_with_stdio(0);
        int ans = 0, sz = nums.size();

        for (int i = 0; i < sz; ++i) {

            for (int j = i + 1; j < sz; ++j) {

                for (int k = j + 1; k < sz; ++k) {
                    if (nums[j] - nums[i] == diff &&
                        nums[k] - nums[j] == diff) {
                        ans += 1;
                    }
                }
            }
        }
        return ans;
    }
};