find immediate neighbors (north, east, south, west) of any tile #n in a 25x25 grid in swift in swift

Assuming a 2D array is used, the immediate neighbors of any tile #n (i,j) in a 25x25 grid can be found as follows:

main.swift
let N = 25
let i = n / N
let j = n % N

// north
if i > 0 {
    let northNeighbor = (i-1)*N + j
}

// south
if i < N-1 {
    let southNeighbor = (i+1)*N + j
}

// west
if j > 0 {
    let westNeighbor = i*N + (j-1)
}

// east
if i < N-1 {
    let eastNeighbor = i*N + (j+1)
}
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The above code assumes that n is the index of the tile, starting from 0. It calculates the indices i and j of the tile in the 2D array. Then, it checks whether the tile has a neighbor in the north, south, west, or east direction, and calculates the index of that neighbor in the array. The neighbor indexes are calculated based on the assumption that the array is arranged row by row, from top to bottom.

Note that the code does not handle corner cases, where a tile does not have a neighbor in some direction. In those cases, the corresponding neighbor variables will not be defined.