25 lines
624 B
Go
25 lines
624 B
Go
// Package q790 implements a solution for https://leetcode.com/problems/domino-and-tromino-tiling/
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package q790
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const (
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TopHalf int8 = iota
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BottomHalf
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Full
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Modulo int = 1e9 + 7
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)
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func numTilings(n int) int {
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cache := make([][3]int, n+1)
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cache[0][Full] = 1
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cache[1][Full] = 1
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for w := 2; w <= n; w++ {
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cache[w][Full] = (cache[w-1][Full] + cache[w-2][Full] + cache[w-1][TopHalf] + cache[w-1][BottomHalf]) % Modulo
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cache[w][TopHalf] = (cache[w-1][BottomHalf] + cache[w-2][Full]) % Modulo
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cache[w][BottomHalf] = (cache[w-1][TopHalf] + cache[w-2][Full]) % Modulo
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}
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return cache[n][Full]
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}
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var _ = numTilings
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