Package g0901_1000.s0935_knight_dialer
Class Solution
java.lang.Object
g0901_1000.s0935_knight_dialer.Solution
935 - Knight Dialer.<p>Medium</p>
<p>The chess knight has a <strong>unique movement</strong> , 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 <strong>L</strong> ). The possible movements of chess knight are shown in this diagaram:</p>
<p>A chess knight can move as indicated in the chess diagram below:</p>
<p><img src="https://assets.leetcode.com/uploads/2020/08/18/chess.jpg" alt="" /></p>
<p>We have a chess knight and a phone pad as shown below, the knight <strong>can only stand on a numeric cell</strong> (i.e. blue cell).</p>
<p><img src="https://assets.leetcode.com/uploads/2020/08/18/phone.jpg" alt="" /></p>
<p>Given an integer <code>n</code>, return how many distinct phone numbers of length <code>n</code> we can dial.</p>
<p>You are allowed to place the knight <strong>on any numeric cell</strong> initially and then you should perform <code>n - 1</code> jumps to dial a number of length <code>n</code>. All jumps should be <strong>valid</strong> knight jumps.</p>
<p>As the answer may be very large, <strong>return the answer modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>
<p><strong>Example 1:</strong></p>
<p><strong>Input:</strong> n = 1</p>
<p><strong>Output:</strong> 10</p>
<p><strong>Explanation:</strong> We need to dial a number of length 1, so placing the knight over any numeric cell of the 10 cells is sufficient.</p>
<p><strong>Example 2:</strong></p>
<p><strong>Input:</strong> n = 2</p>
<p><strong>Output:</strong> 20</p>
<p><strong>Explanation:</strong> 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]</p>
<p><strong>Example 3:</strong></p>
<p><strong>Input:</strong> n = 3131</p>
<p><strong>Output:</strong> 136006598</p>
<p><strong>Explanation:</strong> Please take care of the mod.</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>1 <= n <= 5000</code></li>
</ul>
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Constructor Summary
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Method Summary
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Solution
public Solution()
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Method Details
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knightDialer
public int knightDialer(int n)
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