Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time complexity. Credits:Special thanks to @ts for adding this problem and creating all test cases. 这道题并没有什么难度,是让求一个数的阶乘末尾0的个数,也就是要找乘数中10的个数,…

C. Drazil and Factorial time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Drazil is playing a math game with Varda. Let's define for positive integer x as a product of factorials of its digi…

LeetCode上的原题,讲解请参见我之前的博客Factorial Trailing Zeroes. 解法一: int trailing_zeros(int n) { ; while (n) { res += n / ; n /= ; } return res; } 解法二: int trailing_zeros(int n) { ? : n / + trailing_zeros(n / ); } CareerCup All in One 题目汇总…

[codeforces 516]A. Drazil and Factorial 试题描述 Drazil is playing a math game with Varda. Let's define  for positive integer x as a product of factorials of its digits. For example, . First, they choose a decimal number a consisting of n digits that con…

原题链接在这里:https://leetcode.com/problems/factorial-trailing-zeroes/ 求factorial后结尾有多少个0,就是求有多少个2和5的配对. 但是2比5多了很多,所以就是求5得个数.但是有的5是叠加起来的比如 25,125是5的幂数,所以就要降幂. e.g. n = 100, n/5 =20, n/25= 4, n/125=0,所以加起来就有24个0. O(logn)解法: 一个更聪明的解法是:考虑n!的质数因子.后缀0总是由质因子2和质因…

Factorial Trailing Zeroes Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time complexity. Credits:Special thanks to @ts for adding this problem and creating all test cases. 对n!做质因数分解n!=2x*…

Counting trailing 0s of n! It is not very hard to figure out how to count it - simply count how many 5s. Since even numbers are always more than 5s, we don't have to consider even numbers. But counting 5, is tricky. Naive method is quite slow - I got…

题目链接:https://projecteuler.net/problem=74 数字145有一个著名的性质:其所有位上数字的阶乘和等于它本身. 1! + 4! + 5! = 1 + 24 + 120 = 145 169不像145那么有名,但是169可以产生最长的能够连接回它自己的数字链.事实证明一共有三条这样的链: 169 --> 363601 -->  1454 -->  169871 -->  45361 -->  871872 -->  45362 -->…

Drazil and Factorial time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Drazil is playing a math game with Varda. Let's define  for positive integer x as a product of factorials of its digits…

Factorial  计算阶乘 In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example: 5! = 5 * 4 * 3 * 2 * 1 = 120. By convention the value of 0! is 1. Write a function…