Class Solution

java.lang.Object
g0901_1000.s0935_knight_dialer.Solution

public class Solution extends Object
935 - Knight Dialer\. Medium The chess knight has a **unique movement** , it may move two squares vertically and one square horizontally, or two squares horizontally and one square vertically (with both forming the shape of an **L** ). The possible movements of chess knight are shown in this diagaram: A chess knight can move as indicated in the chess diagram below: ![](https://assets.leetcode.com/uploads/2020/08/18/chess.jpg) We have a chess knight and a phone pad as shown below, the knight **can only stand on a numeric cell** (i.e. blue cell). ![](https://assets.leetcode.com/uploads/2020/08/18/phone.jpg) Given an integer `n`, return how many distinct phone numbers of length `n` we can dial. You are allowed to place the knight **on any numeric cell** initially and then you should perform `n - 1` jumps to dial a number of length `n`. All jumps should be **valid** knight jumps. As the answer may be very large, **return the answer modulo** 109 + 7. **Example 1:** **Input:** n = 1 **Output:** 10 **Explanation:** We need to dial a number of length 1, so placing the knight over any numeric cell of the 10 cells is sufficient. **Example 2:** **Input:** n = 2 **Output:** 20 **Explanation:** All the valid number we can dial are [04, 06, 16, 18, 27, 29, 34, 38, 40, 43, 49, 60, 61, 67, 72, 76, 81, 83, 92, 94] **Example 3:** **Input:** n = 3131 **Output:** 136006598 **Explanation:** Please take care of the mod. **Constraints:** * `1 <= n <= 5000`
  • Constructor Details

    • Solution

      public Solution()
  • Method Details

    • knightDialer

      public int knightDialer(int n)