From 08706ec1573fc883cf01dc67fbecd2a92808fe04 Mon Sep 17 00:00:00 2001
From: SeonjaeLee <tjswo9502@gmail.com>
Date: Wed, 13 Nov 2024 17:39:17 +0900
Subject: [PATCH] 3. House Robber II

---
 house-robber-ii/sunjae95.js | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 house-robber-ii/sunjae95.js

diff --git a/house-robber-ii/sunjae95.js b/house-robber-ii/sunjae95.js
new file mode 100644
index 000000000..468f37fc9
--- /dev/null
+++ b/house-robber-ii/sunjae95.js
@@ -0,0 +1,31 @@
+/**
+ * @description
+ * 점화식: dp[i] = Math.max(dp[i - 1], dp[i - 2] + current);
+ * 순회한다는 조건이 있으므로 다음과 같이 분기처리 할 수 있다.
+ * 1. 처음이 선택 O 마지막 X
+ * 2. 처음이 선택 X 마지막 상관없음
+ *
+ * n = length of nums
+ * time complexity: O(n)
+ * space complexity: O(n)
+ */
+var rob = function (nums) {
+  if (nums.length === 1) return nums[0];
+  if (nums.length === 2) return Math.max(nums[0], nums[1]);
+
+  const hasFirst = Array.from({ length: nums.length }, (_, i) =>
+    i < 2 ? nums[0] : 0
+  );
+  const noFirst = Array.from({ length: nums.length }, (_, i) =>
+    i === 1 ? nums[i] : 0
+  );
+  for (let i = 2; i < nums.length; i++) {
+    hasFirst[i] = Math.max(hasFirst[i - 1], hasFirst[i - 2] + nums[i]);
+    noFirst[i] = Math.max(noFirst[i - 1], noFirst[i - 2] + nums[i]);
+    if (i === nums.length - 1) {
+      hasFirst[i] = Math.max(hasFirst[i - 1], hasFirst[i - 2]);
+    }
+  }
+
+  return Math.max(hasFirst[nums.length - 1], noFirst[nums.length - 1]);
+};