feat: house-robber

Author: minji-go

house-robber/minji-go.java

@@ -1,19 +1,26 @@
-/*
-    Problem: https://leetcode.com/problems/house-robber/
-    Description: the maximum amount of money you can rob if you cannot rob two adjacent houses
-    Concept: Array, Dynamic Programming
-    Time Complexity: O(n), Runtime: 0ms
-    Space Complexity: O(1), Memory: 41.42MB
-*/
+/**
+ * <a href="https://leetcode.com/problems/house-robber/">week01-5.house-robber</a>
+ * <li> Description: the maximum amount of money you can rob if you cannot rob two adjacent houses  </li>
+ * <li> Concept: Array, Dynamic Programming     </li>
+ * <li> Time Complexity: O(n), Runtime: 0ms     </li>
+ * <li> Space Complexity: O(1), Memory: 41.1MB  </li>
+ */
+
 class Solution {
     public int rob(int[] nums) {
-        int sum1 = nums[0];
-        int sum2 = nums.length>1? Math.max(nums[0], nums[1]) : nums[0];
-        for(int i=2; i<nums.length; i++){
-            int sum3=Math.max(nums[i]+sum1,sum2);
-            sum1=sum2;
-            sum2=sum3;
+        if(nums.length==1) {
+            return nums[0];
         }
-        return sum2;
+
+        List<Integer> money = new ArrayList<>();
+        money.add(nums[0]);
+        money.add(Math.max(nums[0], nums[1]));
+
+        for(int i=2; i<nums.length; i++) {
+            money.set(0, Math.max(money.get(0)+nums[i], money.get(1)));
+            Collections.swap(money, 0 , 1);
+        }
+
+        return money.get(1);
     }
 }