Package g0801_0900.s0837_new_21_game

Class Solution

java.lang.Object
g0801_0900.s0837_new_21_game.Solution
public class Solution extends java.lang.Object
837 - New 21 Game.

Medium

Alice plays the following game, loosely based on the card game “21”.

Alice starts with 0 points and draws numbers while she has less than k points. During each draw, she gains an integer number of points randomly from the range [1, maxPts], where maxPts is an integer. Each draw is independent and the outcomes have equal probabilities.

Alice stops drawing numbers when she gets k or more points.

Return the probability that Alice has n or fewer points.

Answers within 10-5 of the actual answer are considered accepted.

Example 1:

Input: n = 10, k = 1, maxPts = 10

Output: 1.00000

Explanation: Alice gets a single card, then stops.

Example 2:

Input: n = 6, k = 1, maxPts = 10

Output: 0.60000

Explanation: Alice gets a single card, then stops. In 6 out of 10 possibilities, she is at or below 6 points.

Example 3:

Input: n = 21, k = 17, maxPts = 10

Output: 0.73278

Constraints:

  • 0 <= k <= n <= 104
  • 1 <= maxPts <= 104

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    new21Game(int n, int k, int w)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • new21Game

      public double new21Game(int n, int k, int w)