func countBlackBlocks(m int, n int, coordinates [][]int) []int64 {        key := func(i, j int) int64 {            return int64(i) * int64(n) + int64(j)        }                M := make(map[int64]int64, 1024)                for _, cell := range coordinates {            i, j := cell[0], cell[1]                        for x := i-1; x <= i; x++ {                for y := j-1; y <= j; y++ {                    if (x >= 0 && x < m-1 && y >= 0 && y < n-1) {                        M[key(x, y)]++                    }                }            }        }                result := []int64{0, 0, 0, 0, 0}                for _, v := range M {            result[v]++        }                result[0] = int64(m-1)*int64(n-1) - result[1] - result[2] - result[3] - result[4]                return result    }