update

Author: realdennis

src/house-robber-ii.ts

@@ -0,0 +1,24 @@
+function rob(nums: number[]): number {
+  /**
+   * One pass loop, constant space
+   */
+  const N = nums.length;
+  if (N <= 3) return Math.max(...nums); // we really don't care
+
+  let next2 = nums[N - 1];
+  let next1 = Math.max(nums[N - 1], nums[N - 2]);
+
+  let nnext2 = nums[N - 2];
+  let nnext1 = Math.max(nums[N - 2], nums[N - 3]);
+
+  for (let i = N - 3; i >= 1; i--) {
+    const val = Math.max(nums[i] + next2, next1);
+    next2 = next1;
+    next1 = val;
+
+    const vval = Math.max(nums[i - 1] + nnext2, nnext1);
+    nnext2 = nnext1;
+    nnext1 = vval;
+  }
+  return Math.max(next1, nnext1);
+}