[BOJ 16998] It’s a Mod, Mod, Mod, Mod World
16998번: It’s a Mod, Mod, Mod, Mod World You are given multiple problems with three integers p, q, and n. Find \(\displaystyle\sum_{i=1}^{n}{((p \cdot i) \text{ mod } q)}\). That is, the first n multiples of p, modulo q, summed. Note that the overall sum has no modulus. www.acmicpc.net 풀이가 적혀있던 노트를 겨우 찾아서 포스팅한다. ㅎㅎ ㅠ 풀이 $x\%m=x-(x/m)*m$ 임을 이용해 주어진 식을 변형하면 $ans=\frac{n(n+1)}{2}p-q\sum_{i=1}^{n}\le..
