Create 0427-construct-quad-tree.kt

Author: a93a

Diff for: kotlin/0427-construct-quad-tree.kt

@@ -0,0 +1,44 @@
+/**
+ * Definition for a QuadTree node.
+ * class Node(var `val`: Boolean, var isLeaf: Boolean) {
+ *     var topLeft: Node? = null
+ *     var topRight: Node? = null
+ *     var bottomLeft: Node? = null
+ *     var bottomRight: Node? = null
+ * }
+ */
+
+class Solution {
+    fun construct(grid: Array<IntArray>): Node? {
+
+        fun dfs(n: Int, r: Int, c: Int): Node? {
+            var allSame = true
+
+            for(i in 0 until n) {
+                for(j in 0 until n) {
+                    if(grid[r][c] != grid[r + i][c + j]) {
+                        allSame = false
+                        break
+                    }
+                }
+            }
+
+            if(allSame) return Node(if(grid[r][c] == 1) true else false, true)
+
+            val nextN = n/2
+            val topLeft = dfs(nextN, r, c)
+            val topRight = dfs(nextN, r, c + nextN)
+            val bottomLeft = dfs(nextN, r + nextN, c)
+            val bottomRight = dfs(nextN, r + nextN, c + nextN)
+
+            val node = Node(false, false)
+            node.topLeft = topLeft
+            node.topRight = topRight
+            node.bottomLeft = bottomLeft
+            node.bottomRight = bottomRight
+            return node
+        }
+
+        return dfs(grid.size, 0, 0)
+    }
+}