func surfaceArea(grid [][]int) int {
r, c := len(grid), len(grid[0])
area := 0
for i := 0; i < r; i++ {
for j := 0; j < c; j++ {
area += grid[i][j] * 6
if grid[i][j] > 1 {
area -= (grid[i][j] - 1) * 2
}
if j > 0 && grid[i][j-1] > 0 && grid[i][j] > 0 { // 同一行的挨着
area -= min(grid[i][j], grid[i][j-1]) * 2
}
if i > 0 && grid[i-1][j] > 0 && grid[i][j] > 0 { // 同一列挨着
area -= min(grid[i][j], grid[i-1][j]) * 2
}
}
}
return area
}
func min(x, y int) int {
if x > y {
return y
}
return x
}
