def beautifulTriplets(d, arr):
    count=0
    for i in range(0,len(arr)-2):
        for j in range(i+1,len(arr)-1):
            if(abs(arr[i]-arr[j])==d):
                for k in range(j+1,len(arr)):
                    if(abs(arr[j]-arr[k])==d):
                        print(i,j,k)
                        count=count+1
    return count

int beautifulTriplets(int d, vector<int> arr) {
    map<int, int> mp;
    int result = 0;
    for (int a : arr) {
        mp[a] += 1;
        result += mp[a-d]*mp[a-2*d];
    }
    return result;
}

		l=len(arr)
    count=0 
    for i in range(l-2):
        if arr[i]+d in arr and arr[i]+(2*d) in arr:
            count+=1 
    return count

def beautifulTriplets(d, arr):
    return sum(arr.count(n) * arr.count(n + d) * arr.count(n + d + d) for n in set(arr))

def beautifulTriplets(d, arr):
    beautiful = 0
    for i in range(len(arr) - 2):
        for j in range(i + 1, len(arr) - 1):
            if arr[j] - arr[i] == d:
                for k in range(j + 1, len(arr)):
                    if arr[k] - arr[j] == d:
                        beautiful += 1
    return beautiful