Codeforces Round #649 (Div.2) Solution

前言 過久沒打,手速/腦力都不行啦~~html A A A x ∤ s u m , a n s = n x\not| sum,ans=n x​∣sum,ans=n ∀    x ∣ a i , a n s = − 1 \forall~~ x|a_i,ans=-1 ∀  x∣ai​,ans=−1 不然,去掉前綴/後綴 int n,m,l,r,ans; ll s; int main() { i

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