How to solve the House Robber Challenge in Java

The challenge

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security system connected and it will automatically contact the police if two adjacent houses were broken into on the same night.

Given a list of non-negative integers representing the amount of money of each house, determine the maximum amount of money you can rob tonight without alerting the police.

Example 1:

Input: nums = [1,2,3,1]
Output: 4
Explanation: Rob house 1 (money = 1) and then rob house 3 (money = 3).
             Total amount you can rob = 1 + 3 = 4.

Example 2:

Input: nums = [2,7,9,3,1]
Output: 12
Explanation: Rob house 1 (money = 2), rob house 3 (money = 9) and rob house 5 (money = 1).
             Total amount you can rob = 2 + 9 + 1 = 12.

Constraints:

  • 0 <= nums.length <= 100
  • 0 <= nums[i] <= 400

The solution in Java

class Solution {
    public int rob(int[] nums) {
        // catch some edge cases
        if (nums.length==0) return 0;
        if (nums.length==1) return nums[0];
        
        // declare some variables we can check against
        int odds = 0;
        int evens = 0;
        
        // loop through all elements of the array
        for (int i=0; i<nums.length; i++) {
            // keep a local count
            int j = i+1;
            
            if (j%2!=0) {
                // if odd number, update count
                odds += nums[i];
                // force update whichever count is bigger
                odds = evens > odds ? evens : odds;
            } else {
                // if even number, update count
                evens += nums[i];
                // force update whichever count is bigger
                evens = evens > odds ? evens : odds;
            }
        }
        // return whichever count is bigger
        return odds > evens ? odds : evens;
    }
}
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