Added houseRobber2 solution

Author: nhistory

house-robber-ii/nhistory.js

@@ -0,0 +1,20 @@
+var rob = function (nums) {
+  // edge case
+  if (nums.length === 1) return nums[0];
+
+  const dp = (start, end) => {
+    let prev = 0,
+      curr = 0;
+    for (let i = start; i < end; i++) {
+      let temp = curr;
+      curr = Math.max(nums[i] + prev, curr);
+      prev = temp;
+    }
+    return curr;
+  };
+
+  return Math.max(dp(0, nums.length - 1), dp(1, nums.length));
+};
+
+// TC: O(n)
+// SC: O(1)