LeetCode

House Robber II

Note: This is an extension of House Robber.

After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time, all houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, the security system for these houses remain the same as for those in the previous street.

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.

Java

public class Solution {
    public int rob(int[] nums) {
        if(nums.length <= 1) {
            if(nums.length == 1) {
                return nums[0];
            } else {
                return 0;
            }
        }
        return Math.max(robLinear(Arrays.copyOfRange(nums, 0, nums.length - 1)), robLinear(Arrays.copyOfRange(nums, 1, nums.length)));
    }

    public int robLinear(int[] nums) {
        if(nums.length < 1) {
            return 0;
        }
        int[] rst = new int[nums.length + 1];
        rst[0] = 0;
        rst[1] = nums[0];

        int i = 2;
        while(i < nums.length + 1) {
            rst[i] = Math.max(rst[i - 1], rst[i - 2] + nums[i - 1]);
            i++;
        }
        return rst[nums.length];
    }
}