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Contests/LeetCode/Weekly Contest 409/3242. Design Neighbor Sum Service
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Weekly Contest 409

3242. Design Neighbor Sum Service

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Problem Statement

Official algorithmic problem description and constraints.

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You are given a n x n 2D array grid containing distinct elements in the range [0, n2 - 1].

Implement the neighborSum class:

  • neighborSum(int [][]grid) initializes the object.
  • int adjacentSum(int value) returns the sum of elements which are adjacent neighbors of value, that is either to the top, left, right, or bottom of value in grid.
  • int diagonalSum(int value) returns the sum of elements which are diagonal neighbors of value, that is either to the top-left, top-right, bottom-left, or bottom-right of value in grid.

 

Example 1:

Input:

["neighborSum", "adjacentSum", "adjacentSum", "diagonalSum", "diagonalSum"]

[[[[0, 1, 2], [3, 4, 5], [6, 7, 8]]], [1], [4], [4], [8]]

Output: [null, 6, 16, 16, 4]

Explanation:

  • The adjacent neighbors of 1 are 0, 2, and 4.
  • The adjacent neighbors of 4 are 1, 3, 5, and 7.
  • The diagonal neighbors of 4 are 0, 2, 6, and 8.
  • The diagonal neighbor of 8 is 4.

Example 2:

Input:

["neighborSum", "adjacentSum", "diagonalSum"]

[[[[1, 2, 0, 3], [4, 7, 15, 6], [8, 9, 10, 11], [12, 13, 14, 5]]], [15], [9]]

Output: [null, 23, 45]

Explanation:

  • The adjacent neighbors of 15 are 0, 10, 7, and 6.
  • The diagonal neighbors of 9 are 4, 12, 14, and 15.

 

Constraints:

  • 3 <= n == grid.length == grid[0].length <= 10
  • 0 <= grid[i][j] <= n2 - 1
  • All grid[i][j] are distinct.
  • value in adjacentSum and diagonalSum will be in the range [0, n2 - 1].
  • At most 2 * n2 calls will be made to adjacentSum and diagonalSum.


Solutions & Walkthrough

Detailed video explanations, mathematical intuition, and clean C++ implementation code.

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