Re: [Java O(n) solution](space O(1))

@tusizi : Your solution is awesome! I just made a few change to make it easy to understand.

```
public class Solution {
public int rob(int[] nums) {
int prevNo = 0; // max money can get if NOT rob previous house
int prevYes = 0; // max money can get if rob previous house
for (int n : nums) {
//1.Rob the current house
int currYes = prevNo + n; //previous not robbed + current house
//2.Don't rob
int currNo = Math.max(prevNo, prevYes); //Max of the previous cell robbed and not robbed -- Optimal substructure.
//Update values for the next round
prevNo = currNo;
prevYes = currYes;
}
return Math.max(prevNo, prevYes);
}
}
```