solve: maximum depth of binary tree

Author: wogha95

maximum-depth-of-binary-tree/wogha95.js

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+/**
+ * TC: O(N)
+ * 모든 노드를 순회합니다.
+ *
+ * SC: O(N)
+ * 노드의 수에 비례해서 queue의 길이가 증가됩니다.
+ *
+ * N: count of tree node
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function (root) {
+  let maximumDepth = 0;
+
+  const queue = [[root, 1]];
+  while (queue.length > 0) {
+    const [current, depth] = queue.shift();
+
+    if (current === null) {
+      break;
+    }
+
+    maximumDepth = Math.max(maximumDepth, depth);
+
+    if (current.left) {
+      queue.push([current.left, depth + 1]);
+    }
+
+    if (current.right) {
+      queue.push([current.right, depth + 1]);
+    }
+  }
+
+  return maximumDepth;
+};