Update 1740-find-distance-in-a-binary-tree.js

Author: everthis

1740-find-distance-in-a-binary-tree.js

@@ -1,3 +1,43 @@
+/**
+ * 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
+ * @param {number} p
+ * @param {number} q
+ * @return {number}
+ */
+const findDistance = function(root, p, q) {
+  if(p === q) return 0
+  return dfs(root, 0)
+
+  function dfs(node, depth) {
+    let res = depth
+    if (node == null) {
+      res = 0
+    } else if(node.val === p || node.val === q) {
+      let left = dfs(node.left, 1)
+      let right = dfs(node.right, 1)
+      res = (left > 0 || right > 0) ? Math.max(left, right) : res
+    } else {
+      let left = dfs(node.left, depth + 1)
+      let right = dfs(node.right, depth + 1)
+      res = left + right
+      if(left !== 0 && right !== 0) {
+        res -= 2 * depth
+      }
+    }
+    return res
+  }
+};
+
+// another
+
 /**
  * Definition for a binary tree node.
  * function TreeNode(val, left, right) {