Question

198. House Robber

中文文档

Description

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security systems 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 = [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 2:

Input: nums = [2,7,9,3,1]
Output: 12
Explanation: Rob house 1 (money = 2), rob house 3 (money = 9) and rob house 5 (money = 1).
Total amount you can rob = 2 + 9 + 1 = 12.

 

Constraints:

• 1 <= nums.length <= 100
• 0 <= nums[i] <= 400

Solutions

Solution 1

class Solution:
  def rob(self, nums: List[int]) -> int:
    n = len(nums)
    f = [0] * (n + 1)
    f[1] = nums[0]
    for i in range(2, n + 1):
      f[i] = max(f[i - 1], f[i - 2] + nums[i - 1])
    return f[n]

class Solution {
  public int rob(int[] nums) {
    int n = nums.length;
    int[] f = new int[n + 1];
    f[1] = nums[0];
    for (int i = 2; i <= n; ++i) {
      f[i] = Math.max(f[i - 1], f[i - 2] + nums[i - 1]);
    }
    return f[n];
  }
}

class Solution {
public:
  int rob(vector<int>& nums) {
    int n = nums.size();
    int f[n + 1];
    memset(f, 0, sizeof(f));
    f[1] = nums[0];
    for (int i = 2; i <= n; ++i) {
      f[i] = max(f[i - 1], f[i - 2] + nums[i - 1]);
    }
    return f[n];
  }
};

func rob(nums []int) int {
  n := len(nums)
  f := make([]int, n+1)
  f[1] = nums[0]
  for i := 2; i <= n; i++ {
    f[i] = max(f[i-1], f[i-2]+nums[i-1])
  }
  return f[n]
}

function rob(nums: number[]): number {
  const n = nums.length;
  const f: number[] = Array(n + 1).fill(0);
  f[1] = nums[0];
  for (let i = 2; i <= n; ++i) {
    f[i] = Math.max(f[i - 1], f[i - 2] + nums[i - 1]);
  }
  return f[n];
}

impl Solution {
  pub fn rob(nums: Vec<i32>) -> i32 {
    let mut f = [0, 0];
    for x in nums {
      f = [f[0].max(f[1]), f[0] + x];
    }
    f[0].max(f[1])
  }
}

Solution 2

class Solution:
  def rob(self, nums: List[int]) -> int:
    f = g = 0
    for x in nums:
      f, g = max(f, g), f + x
    return max(f, g)

class Solution {
  public int rob(int[] nums) {
    int f = 0, g = 0;
    for (int x : nums) {
      int ff = Math.max(f, g);
      g = f + x;
      f = ff;
    }
    return Math.max(f, g);
  }
}

class Solution {
public:
  int rob(vector<int>& nums) {
    int f = 0, g = 0;
    for (int& x : nums) {
      int ff = max(f, g);
      g = f + x;
      f = ff;
    }
    return max(f, g);
  }
};

func rob(nums []int) int {
  f, g := 0, 0
  for _, x := range nums {
    f, g = max(f, g), f+x
  }
  return max(f, g)
}

function rob(nums: number[]): number {
  let [f, g] = [0, 0];
  for (const x of nums) {
    [f, g] = [Math.max(f, g), f + x];
  }
  return Math.max(f, g);
}