USP

2023 USP Try-outs-A-Lagrange插值 题目链接：https://codeforces.com/gym/104505/problem/A 简化题意：求 \[\frac{\sum_{i=1}^n i^k (n+1-i)^k}{\sum_{i=1}^n i^k} \]其中\(1\l ......