Added subtree of another tree solution with js

Author: nhistory

subtree-of-another-tree/nhistory.js

@@ -0,0 +1,39 @@
+/**
+ * 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 {TreeNode} subRoot
+ * @return {boolean}
+ */
+var isSubtree = function (root, subRoot) {
+  // Make function to check two triangle is same or not
+  const isSame = (root1, root2) => {
+    // If both of root1 and root2 is null, return true
+    if (!root1 && !root2) return true;
+    // If one of root1 and root2 is null or root1.val is not equal to root2.val, return false
+    if (!root1 || !root2 || root1.val !== root2.val) return false;
+    // Compare each left and right value with recursive
+    return isSame(root1.left, root2.left) && isSame(root1.right, root2.right);
+  };
+
+  // Make dfs function to check nodes inside of root tree
+  const dfs = (node) => {
+    // if node is null, return false
+    if (!node) return false;
+    // Check triangle is equal to subRoot
+    if (isSame(node, subRoot)) return true;
+    // Check one of the left or right node is same with triangle
+    return dfs(node.left) || dfs(node.right);
+  };
+  // Execute dfs function
+  return dfs(root);
+};
+
+// TC: O(n*m)
+// SC: O(max(m,n))