Projection Area of 3D Shapes

At first, the problem looks very difficult as it involves multi-dimensional array and projections but the graph in the example really gives out the clue about how to solve this problem.

class Solution {
    fun projectionArea(grid: Array<IntArray>): Int {
        val size = grid.size
        var totalArea = 0
        
        (0 until size).forEach { x ->
            var xMax = 0
            var yMax = 0
            
            (0 until size).forEach { y ->
                xMax = Math.max(xMax, grid[x][y])    
                yMax = Math.max(yMax, grid[y][x])
                
                if(grid[x][y] > 0) totalArea++
            }
            
            totalArea += xMax + yMax
        }
        return totalArea
    }
}
Runtime: 192 ms, faster than 100.00% of Kotlin online submissions for Projection Area of 3D Shapes.
Memory Usage: 36.7 MB, less than 100.00% of Kotlin online submissions for Projection Area of 3D Shapes.
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