开始刷leetcode day63: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.

Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

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 Dynamic Programming

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Java:

public class Solution {
    public int rob(int[] nums) {
        if(nums.length==0) return 0;
        if(nums.length ==1) return nums[0];
        return Math.max(subrob(nums,0,nums.length-2),subrob(nums,1,nums.length-1));
    }
    
    public int subrob(int[] nums, int start, int end)
    {
        int max1 = 0; int max2 = 0;
        
        for(int i = start; i<=end; i++)
        {
            int temp = max1 + nums[i];
            max1 = max2;
            max2 = Math.max(temp, max2);
        }
        
        return Math.max(max1,max2);
    }
}

注意：分成了两种情况：1.包括第一个房子，去掉最后的房子   2.包括最后的房子，去掉第一个房子

对每种情况进行dynamic prg即可