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Why does this code give WA on test 6 ?

By rahulpkvij, history, 5 years ago, In English

https://mirror.codeforces.com/contest/1265/submission/68128052

Can anyone explain why this code is giving WA on test 6 and how do I correct it ? Thanks in advance.

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5 years ago, # |
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Overflow is the cause. In the below line

i*(i-1)*1ll

As the expression is processed from left to right, i*(i-1) is stored in to 'int' first and only then it is multiplied by 1ll. So do 1ll*i*(i-1) to rectify it.

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