Leetcode 3071. Minimum Operations to Write the Letter Y on a Grid

Given an odd n x n grid with values 0–2, find the minimum number of single-cell changes needed so that all cells on the letter Y (the two diagonals to the center plus the central vertical down to the bottom) share one value and all other cells share a different value. This reduces to counting value frequencies among Y and non‑Y cells and choosing two distinct target values that maximize preserved cells.