Add house-robber-ii solution

Author: Jeehay28

house-robber-ii/Jeehay28.js

@@ -0,0 +1,35 @@
+// ✅ Time Complexity: O(n)
+// ✅ Space Complexity: O(1)
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+  // Edge case: If there's only one house, return its value
+  if (nums.length === 1) return nums[0];
+
+  // helper function
+  const robHouses = (start, end) => {
+    // prev1: stores the maximum money robbed up to the previous house.
+    // prev2: stores the maximum money robbed up to the house before the previous house.
+    let prev1 = 0,
+      prev2 = 0;
+
+    for (let i = start; i <= end; i++) {
+      let temp = Math.max(prev1, prev2 + nums[i]);
+
+      prev2 = prev1;
+
+      prev1 = temp;
+    }
+
+    return prev1;
+  };
+
+  // Excluding the last house: robHouses(0, nums.length - 2)
+  // Excluding the first house: robHouses(1, nums.length - 1)
+
+  return Math.max(robHouses(0, nums.length - 2), robHouses(1, nums.length - 1));
+};
+