2022-08-19 08:25:19 +08:00
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# M - Pairs Forming LCM
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* https://vjudge.net/contest/509210#problem/M
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2022-08-18 22:57:16 +08:00
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### <20><><EFBFBD><EFBFBD>
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2022-08-19 08:25:19 +08:00
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<EFBFBD><EFBFBD>n,lcm(i, j) = n and (i <20><> j).
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2022-08-18 22:57:16 +08:00
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### <20><><EFBFBD><EFBFBD>
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2022-08-19 08:25:19 +08:00
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֽ<EFBFBD>n=p1^k1*p2^k2
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ans*=(2k[i]+1);(i=0~k,j=0~k,ȥ<><C8A5><EFBFBD>ظ<EFBFBD><D8B8><EFBFBD>k,k)
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ans=ans/2+1;(i<=j,<2C><><EFBFBD><EFBFBD>k,k)
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2022-08-18 22:57:16 +08:00
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### <20>ؼ<EFBFBD><D8BC><EFBFBD>
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### <20>״<EFBFBD><D7B4><EFBFBD>
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*
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### <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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*
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