Add week 15 solutions: subtree-of-another-tree

Author: gitsunmin

subtree-of-another-tree/gitsunmin.ts

@@ -0,0 +1,29 @@
+/**
+ * https://leetcode.com/problems/subtree-of-another-tree/
+ * time complexity : O(n * m)
+ * space complexity : O(n)
+ */
+
+class TreeNode {
+    val: number;
+    left: TreeNode | null;
+    right: TreeNode | null;
+    constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
+        this.val = val ?? 0;
+        this.left = left ?? null;
+        this.right = right ?? null;
+    }
+}
+
+function isSameTree(p: TreeNode | null, q: TreeNode | null): boolean {
+    if (!p && !q) return true;
+    if (!p || !q || p.val !== q.val) return false;
+
+    return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
+}
+
+function isSubtree(root: TreeNode | null, subRoot: TreeNode | null): boolean {
+    if (!root) return false;
+    if (isSameTree(root, subRoot)) return true;
+    return isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
+}