feat: subtree-of-another-tree

Author: gwbaik9717

subtree-of-another-tree/gwbaik9717.js

@@ -0,0 +1,92 @@
+// n: number of nodes in root, m: number of nodes in subroot
+// Time complexity: O(n*m)
+// Space complexity: O(n)
+
+class _Queue {
+  constructor() {
+    this.q = [];
+    this.front = 0;
+    this.rear = 0;
+  }
+
+  isEmpty() {
+    return this.front === this.rear;
+  }
+
+  push(value) {
+    this.q.push(value);
+    this.rear++;
+  }
+
+  shift() {
+    const rv = this.q[this.front];
+    delete this.q[this.front++];
+    return rv;
+  }
+}
+/**
+ * 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) {
+  const check = (root, subRoot) => {
+    const q = new _Queue();
+    q.push([root, subRoot]);
+
+    while (!q.isEmpty()) {
+      const [node, subNode] = q.shift();
+
+      if (node.val !== subNode.val) {
+        return false;
+      }
+
+      if ((node.left && !subNode.left) || (!node.left && subNode.left)) {
+        return false;
+      }
+
+      if ((node.right && !subNode.right) || (!node.right && subNode.right)) {
+        return false;
+      }
+
+      if (node.left && subNode.left) {
+        q.push([node.left, subNode.left]);
+      }
+
+      if (node.right && subNode.right) {
+        q.push([node.right, subNode.right]);
+      }
+    }
+
+    return true;
+  };
+
+  const q = new _Queue();
+  q.push(root);
+
+  while (!q.isEmpty()) {
+    const current = q.shift();
+
+    if (check(current, subRoot)) {
+      return true;
+    }
+
+    if (current.left) {
+      q.push(current.left);
+    }
+
+    if (current.right) {
+      q.push(current.right);
+    }
+  }
+
+  return false;
+};