fork download
copy 
  1. n = int(input())
  2.  
  3. count = 0
  4. q = 5  # 从5^1开始处理
  5.  
  6. while q <= n:
  7.     max_a = n // q  # 当前q的最大指数
  8.     # 计算sum_{k=1}^n floor(k/q)的总和
  9.     count += (max_a * (max_a - 1) // 2) * q + max_a * (n - max_a * q + 1)
  10.     q *= 5  # 处理下一个5的幂次，如5^2=25，5^3=125等
  11.  
  12. print(count)
Success #stdin #stdout 0.02s 7384KB
comments (?)
stdin
copy 
10
stdout
copy 
7
https://ideone.com/bUef5j
language:
Python (cpython 2.7.16)
created:
3 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!