Create 543.二叉树的直径.js

Author: yinxin630

543.二叉树的直径.js

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+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var diameterOfBinaryTree = function(root) {
+    let result = 0;
+    function dfs(node) {
+        if (!node) {
+            return 0;
+        }
+        const left = dfs(node.left);
+        const right = dfs(node.right);
+        result = Math.max(result, left + right);
+        return 1 + Math.max(left, right);
+    }
+    dfs(root);
+    return result;
+};