Get Triplet Count
IBM● MediumFULLTIMEOAProblem statement
The cost of a stock on each day is given in an integer array arr. Count the number of distinct index triplets (i, j, k) such that i < j < k and (arr[i] + arr[j] + arr[k]) is divisible by d.
Return the total number of qualifying triplets. Equal values at different indices represent distinct choices.
Function
getTripletCount(arr: int[], d: int) → intExamples
Example 1
arr = [3, 3, 4, 7, 8]d = 5return = 3
The triplets whose sum is divisible by d are shown.
- Triplet with indices - (0, 1, 2), sum = 3+3+4 = 10
- Triplet with indices - (0, 2, 4), sum = 3+4+8 = 15
- Triplet with indices - (1, 2, 4), sum = 3+4+8 = 15
Hence, the answer is 3.
Constraints
3 <= arr.length <= 2000.-10^9 <= arr[i] <= 10^9.1 <= d <= 10^9.- The answer fits in a signed 32-bit integer.