11 lines
262 B
Python
11 lines
262 B
Python
memo = {0: 0, 2: 3}
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def solution(n):
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if n in memo:
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return memo[n]
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if n % 2 == 1:
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return 0
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answer = sum([solution(i*2) * 2 for i in range((n-2)//2)] + [solution(n-2) * 3] + [2])
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memo[n] = answer
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return answer % 1000000007
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