[heony704] 24.11.19 (#102)

* 102 / Binary Tree Level Order Traversal / Medium / 36m

* 150 / Evaluate Reverse Polish Notation / Medium / 40m

* 572 / Subtree of Another Tree / Easy / 39m

Author: heony704

heony704/102_binary-tree-level-order-traversal.js

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+/**
+ * https://leetcode.com/problems/binary-tree-level-order-traversal/
+ * 36m
+ */
+
+/**
+ * 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
+ * @return {number[][]}
+ */
+var levelOrder = function (root) {
+  const levelOrders = [];
+  let targetNodes = [root];
+
+  while (root) {
+    const nextTargets = [];
+    const currentLevels = [];
+    for (const targetNode of targetNodes) {
+      currentLevels.push(targetNode.val);
+
+      if (targetNode.left !== null) nextTargets.push(targetNode.left);
+      if (targetNode.right !== null) nextTargets.push(targetNode.right);
+    }
+    levelOrders.push(currentLevels);
+    if (nextTargets.length < 1) break;
+    targetNodes = nextTargets;
+  }
+
+  return levelOrders;
+};

heony704/150_evaluate-reverse-polish-notation.js

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+/**
+ * https://leetcode.com/problems/evaluate-reverse-polish-notation/
+ * 40m
+ */
+
+/**
+ * @param {string[]} tokens
+ * @return {number}
+ */
+var evalRPN = function (tokens) {
+  const numStack = [];
+
+  for (const token of tokens) {
+    if (Number.isInteger(Number(token))) {
+      numStack.push(Number(token));
+    } else {
+      const second = numStack.pop();
+      const first = numStack.pop();
+
+      if (token === "+") numStack.push(first + second);
+      if (token === "-") numStack.push(first - second);
+      if (token === "*") numStack.push(first * second);
+      if (token === "/") numStack.push(Math.trunc(first / second));
+    }
+  }
+
+  return numStack[0];
+};

heony704/572_subtree-of-another-tree.js

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+/**
+ * https://leetcode.com/problems/subtree-of-another-tree/
+ * 39m
+ */
+
+/**
+ * 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 isSameTree = function (one, theOther) {
+  if (!one && !theOther) return true;
+  else if (!one || !theOther) return false;
+  if (one.val !== theOther.val) return false;
+  if (!isSameTree(one.left, theOther.left)) return false;
+  if (!isSameTree(one.right, theOther.right)) return false;
+
+  return true;
+};
+
+var isSubtree = function (root, subRoot) {
+  if (isSameTree(root, subRoot)) return true;
+
+  if (root.left && isSubtree(root.left, subRoot)) return true;
+  if (root.right && isSubtree(root.right, subRoot)) return true;
+
+  return false;
+};