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.

Solution:

public class Solution {
    public int rob(int[] nums) {
        if(nums.length==1) return nums[0];
        return Math.max(rob(nums,0,nums.length-2),rob(nums,1,nums.length-1));
    }
    public int rob(int[] nums, int start, int end){
        int exclude = 0, include = 0;
        for(int j=start; j<=end; j++){
            int e = exclude, i = include;
            include = e + nums[j];
            exclude = Math.max(e, i);
        }
        return Math.max(exclude, include);
    }
}
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