213. House Robber II
/*
* @lc app=leetcode id=213 lang=cpp
*
* [213] House Robber II
*
* https://leetcode.com/problems/house-robber-ii/description/
*
* algorithms
* Medium (42.73%)
* Likes: 10281
* Dislikes: 169
* Total Accepted: 937.1K
* Total Submissions: 2.2M
* Testcase Example: '[2,3,2]'
*
* You are a professional robber planning to rob houses along a street. Each
* house has a certain amount of money stashed. All houses at this place are
* arranged in a circle. That means the first house is the neighbor of the last
* one. Meanwhile, adjacent houses have a security system connected, and it
* will automatically contact the police if two adjacent houses were broken
* into on the same night.
*
* Given an integer array nums representing the amount of money of each house,
* return the maximum amount of money you can rob tonight without alerting the
* police.
*
*
* Example 1:
*
*
* Input: nums = [2,3,2]
* Output: 3
* Explanation: You cannot rob house 1 (money = 2) and then rob house 3 (money
* = 2), because they are adjacent houses.
*
*
* Example 2:
*
*
* Input: nums = [1,2,3,1]
* Output: 4
* Explanation: Rob house 1 (money = 1) and then rob house 3 (money = 3).
* Total amount you can rob = 1 + 3 = 4.
*
*
* Example 3:
*
*
* Input: nums = [1,2,3]
* Output: 3
*
*
*
* Constraints:
*
*
* 1 <= nums.length <= 100
* 0 <= nums[i] <= 1000
*
*
*/
// @lc code=start
class Solution {
public:
int rob(vector<int>& nums)
{
int n = nums.size();
if (n == 1) return nums[0];
int excludeLast = robRange(nums, 0, n - 1);
int excludeFirst = robRange(nums, 1, n);
return max(excludeLast, excludeFirst);
}
int robRange(vector<int>& nums, int left, int right)
{
int robbed = 0, notRobbed = 0;
for (int i = left; i < right; ++i)
{
int prevRobbed = robbed;
robbed = max(robbed, nums[i] + notRobbed);
notRobbed = prevRobbed;
}
return robbed;
}
};
// @lc code=end
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