# House Robber

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: [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: [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.
```

## Solution

We need to keep previous and current max to make sure houses are not adjacent.

![](https://1235041943-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M3wXpaIhjJ_SlPm0Aby%2F-M3xQuAc6KNxHBkGu8tD%2F-M3xR2tZ2KO7rOhsCmMl%2Fhouse-robber.png?generation=1585873710855484\&alt=media)Here is algorithm.

```
class Solution {
    public int rob(int[] nums) {
        int prevMax = 0;
        int currMax = 0;
        for (int i = 0; i < nums.length; i++) {
            int val = nums[i];
            int temp = currMax;
            currMax = Math.max(prevMax + val, currMax);
            prevMax = temp;
        }
        return currMax;
    }
}
```