代码随想录算法训练营第四十七天|198.打家劫舍、213.打家劫舍II、337.打家劫舍III

198.打家劫舍

• 刷题https://leetcode.cn/problems/house-robber/description/
• 文章讲解https://programmercarl.com/0198.%E6%89%93%E5%AE%B6%E5%8A%AB%E8%88%8D.html
• 视频讲解https://www.bilibili.com/video/BV1Te411N7SX/?vd_source=af4853e80f89e28094a5fe1e220d9062

• 题解：

// 动态规划
class Solution {
	public int rob(int[] nums) {
		if (nums == null || nums.length == 0) return 0;
		if (nums.length == 1) return nums[0];
 
		int[] dp = new int[nums.length];
		dp[0] = nums[0];
		dp[1] = Math.max(dp[0], nums[1]);
		for (int i = 2; i < nums.length; i++) {
			dp[i] = Math.max(dp[i - 1], dp[i - 2] + nums[i]);
		}
 
		return dp[nums.length - 1];
	}
}

213.打家劫舍II

• 刷题https://leetcode.cn/problems/house-robber-ii/description/
• 文章讲解https://programmercarl.com/0213.%E6%89%93%E5%AE%B6%E5%8A%AB%E8%88%8DII.html
• 视频讲解https://www.bilibili.com/video/BV1oM411B7xq/?vd_source=af4853e80f89e28094a5fe1e220d9062

• 题解：

class Solution {
    public int rob(int[] nums) {
        if (nums == null || nums.length == 0)
            return 0;
        int len = nums.length;
        if (len == 1)
            return nums[0];
        return Math.max(robAction(nums, 0, len - 1), robAction(nums, 1, len));
    }
 
    int robAction(int[] nums, int start, int end) {
        int x = 0, y = 0, z = 0;
        for (int i = start; i < end; i++) {
            y = z;
            z = Math.max(y, x + nums[i]);
            x = y;
        }
        return z;
    }
}

337.打家劫舍III

• 刷题https://leetcode.cn/problems/house-robber-iii/description/
• 文章讲解https://programmercarl.com/0337.%E6%89%93%E5%AE%B6%E5%8A%AB%E8%88%8DIII.html
• 视频讲解https://www.bilibili.com/video/BV1H24y1Q7sY/?vd_source=af4853e80f89e28094a5fe1e220d9062

• 题解：

class Solution {
    public int rob(TreeNode root) {
        if (root == null)
            return 0;
        int money = root.val;
        if (root.left != null) {
            money += rob(root.left.left) + rob(root.left.right);
        }
        if (root.right != null) {
            money += rob(root.right.left) + rob(root.right.right);
        }
        return Math.max(money, rob(root.left) + rob(root.right));
    }
}