Leetcode Problem 1714. Sum Of Special Evenly-Spaced Elements In Array

1714. Sum Of Special Evenly-Spaced Elements In Array

Leetcode Solutions

Prefix Sum with Square Root Decomposition

  1. Define a constant MOD for the modulo operation.
  2. Calculate the square root of the length of the nums array and store it in a variable dividingPoint.
  3. Initialize a dictionary prefix to store prefix sums for step sizes up to dividingPoint.
  4. Precompute prefix sums for each step size y up to dividingPoint and for each possible starting point.
  5. Iterate over each query [x, y].
  6. If y is greater than dividingPoint, compute the sum on the fly by iterating from x to the end of nums, incrementing by y each time.
  7. If y is less than or equal to dividingPoint, use the precomputed prefix sum to find the answer in constant time.
  8. Append the result of each query to the res list after applying the modulo operation.
  9. Return the res list.
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