超级鸡蛋掉落
Super Egg Drop
题目详情
问题:超级鸡蛋掉落
考察:动态规划
来源:Citadel
链接:https://www.jointaro.com/interviews/questions/super-egg-drop/
You are given k identical eggs and you have access to a building with n floors labeled from 1 to n.
You know that there exists a floor f where 0 <= f <= n such that any egg dropped at a floor higher than f will break, and any egg dropped at or below floor f will not break.
Each move, you may take an unbroken egg and drop it from any floor x (where 1 <= x <= n). If the egg breaks, you can no longer use it. However, if the egg does not break, you may reuse it in future moves.
Return the minimum number of moves that you need to determine with certainty what the value of f is.
Example 1:
Input: k = 1, n = 2 Output: 2 Explanation: Drop the egg from floor 1. If it breaks, we know that f = 0. Otherwise, drop the egg from floor 2. If it breaks, we know that f = 1. If it does not break, then we know f = 2. Hence, we need at minimum 2 moves to determine with certainty what the value of f is.
Example 2:
Input: k = 2, n = 6 Output: 3
Example 3:
Input: k = 3, n = 14 Output: 4
Constraints:
1 <= k <= 1001 <= n <= 104
解析
思路:用 dp[m][k] 表示 k 个鸡蛋、m 次移动最多能确定多少层。转移为 dp[m][k] = dp[m-1][k-1] + dp[m-1][k] + 1,逐步增加 m 直到覆盖 n 层。
复杂度:时间 O(k * answer),空间 O(k)。