add House Robber II solution

Author: HoonDongKang

house-robber-ii/HoonDongKang.ts

@@ -0,0 +1,50 @@
+/**
+ * [Problem]: [213] House Robber II
+ * (https://leetcode.com/problems/house-robber-ii/description/)
+ */
+function rob(nums: number[]): number {
+    //시간복잡도 O(n)
+    //공간복잡도 O(n)
+    function memoizationFunc(nums: number[]): number {
+        const memo = new Map<string, number>();
+        const length = nums.length;
+
+        function dfs(idx: number, first = false) {
+            const key = `${idx}_${first}`;
+            if (memo.has(key)) return memo.get(key)!;
+
+            if (idx === length - 1) return first ? 0 : nums[idx];
+            if (idx >= length) return 0;
+            if (idx === 0) {
+                const result = Math.max(nums[0] + dfs(2, true), dfs(1, false));
+                memo.set(key, result);
+                return result;
+            }
+
+            const result = Math.max(nums[idx] + dfs(idx + 2, first), dfs(idx + 1, first));
+            memo.set(key, result);
+            return result;
+        }
+
+        return dfs(0);
+    }
+
+    //시간복잡도 O(n)
+    //공간복잡도 O(1)
+    function dpFunc(nums: number[]): number {
+        if (nums.length === 1) return nums[0];
+
+        function dp(start: number, end: number) {
+            let prev = 0;
+            let cur = 0;
+
+            for (let i = start; i < end; i++) {
+                [prev, cur] = [cur, Math.max(prev + nums[i], cur)];
+            }
+
+            return cur;
+        }
+
+        return Math.max(dp(0, nums.length - 1), dp(1, nums.length));
+    }
+}