LeetCode 213. House Robber II（小偷游戏）

原题网址：https://leetcode.com/problems/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.

方法：动态规划，根据是否从第一个房子开始，分开两种情况计算。

public class Solution {    public int rob(int[] nums) {        if (nums == null || nums.length == 0) return 0;        if (nums.length == 1) return nums[0];        if (nums.length == 2) return Math.max(nums[0], nums[1]);        int max = 0;        int[] money = new int[nums.length];        money[0] = nums[0];        money[1] = Math.max(nums[0], nums[1]);        for(int i=2; i<nums.length-1; i++) {            money[i] = Math.max(money[i-2] + nums[i], money[i-1]);        }        max = Math.max(max, money[nums.length-2]);        Arrays.fill(money, 0);        money[1] = nums[1];        money[2] = Math.max(nums[1], nums[2]);        for(int i=3; i<nums.length; i++) {            money[i] = Math.max(money[i-2] + nums[i], money[i-1]);        }        max = Math.max(max, money[nums.length-1]);        return max;    }}