Create 965-univalued-binary-tree.js

Author: everthis

965-univalued-binary-tree.js

@@ -0,0 +1,26 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {boolean}
+ */
+const isUnivalTree = function(root) {
+  const arr = []
+  dfs(root, arr)
+  for(let i = 1; i < arr.length; i++) {
+    if(arr[i] !== arr[i- 1]) return false
+  }
+  return true
+};
+
+function dfs(node, arr) {
+  if(node === null) return
+  arr.push(node.val)
+  dfs(node.left, arr)
+  dfs(node.right, arr)
+}