solve: binary tree level order traversal

Author: JustHm

binary-tree-level-order-traversal/JustHm.swift

@@ -0,0 +1,17 @@
+// 재귀 함수로 해결
+// 각 노드의 레벨을 기억하고있다가 정답변수에 레벨별로 노드값을 넣어줌
+class Solution {
+    func levelOrder(_ root: TreeNode?) -> [[Int]] {
+        var answer = [[Int]]()
+        searchNodes(0, root, &answer)
+        return answer
+    }
+
+    func searchNodes(_ level: Int, _ node: TreeNode?, _ answer: inout [[Int]]) {
+        guard let node else { return }
+        if level >= answer.count { answer.append([]) }
+        answer[level].append(node.val)
+        searchNodes(level + 1, node.left, &answer)
+        searchNodes(level + 1, node.right, &answer)
+    }
+}