solves projection area of 3d shapes

Author: anishLearnsToCode

README.md

@@ -237,7 +237,7 @@
 | 872 | [Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees) | [![Java](assets/java.png)](src/LeafSimilarTrees.java) |
 | 874 | [Walking Robot Simulation](https://leetcode.com/problems/walking-robot-simulation) | |
 | 876 | [Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list) | [![Java](assets/java.png)](src/MiddleOfTheLinkedList.java) |
-| 883 | [Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes) | |
+| 883 | [Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes) | [![Java](assets/java.png)](src/ProjectionAreaOf3DShapes.java) |
 | 884 | [Uncommon Words from 2 Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences) | |
 | 888 | [Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap) | |
 | 892 | [Surface Area of 3D Shapes](https://leetcode.com/problems/surface-area-of-3d-shapes) | |

src/ProjectionAreaOf3DShapes.java

@@ -0,0 +1,29 @@
+import java.util.Arrays;
+
+public class ProjectionAreaOf3DShapes {
+    public int projectionArea(int[][] grid) {
+        int area = 0;
+        final int n = grid.length;
+
+        // z axis
+        for (int row = 0 ; row < n  ; row++) {
+            for(int column = 0 ; column < n ; column++) {
+                area += grid[row][column] > 0 ? 1 : 0;
+            }
+        }
+
+        // x axis
+        for (int[] row : grid) {
+            area += Arrays.stream(row).max().getAsInt();
+        }
+
+        // y axis
+        for (int column = 0 ; column < n ; column++) {
+            int columnMax = 0;
+            for (int row = 0 ; row < n ; row++) columnMax = Math.max(columnMax, grid[row][column]);
+            area += columnMax;
+        }
+
+        return area;
+    }
+}