213. House Robber II

最新推荐文章于 2025-04-14 23:34:52 发布

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最新推荐文章于 2025-04-14 23:34:52 发布

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分类专栏：数据结构与算法文章标签： Leetcode 算法

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解决一个经典的动态规划问题，环形房屋抢劫问题。探讨如何在一圈排列的房屋中选择最佳的抢劫策略，确保不会因抢劫相邻房屋而触发警报。

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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.

题解

接上题
只是这次变成了一个圈，也就是第一个和最后一个也算作相邻
那么有两种情况：
1. 不取最后一个，即0~n-2
2. 不取第一个，即1~n-1
（注意特殊情况的判断，只有一个时直接返回）

class Solution {
public:
    int rob(vector<int>& nums) {
        int n = nums.size(); 
        if (n < 2) return n ? nums[0] : 0;
        return max(robber(nums, 0, n - 2), robber(nums, 1, n - 1));
    }
private:
    int robber(vector<int>& nums, int l, int r) {
        int pre = 0, cur = 0;
        for (int i = l; i <= r; i++) {
            int temp = cur;
            cur = max(pre + nums[i], cur);
            pre = temp;
        }
        return cur;
    }
};