Software Engineering

# 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;

// 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;
}
}
``````