题目要求是: The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832. 7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319…

题目要求是: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. 这个题目提供两种方法来计算. 方法一:采用最笨拙的方式,直接从1到1000,每一个数都去看看是否可以被3或者5整除…

[题目]GCD of Divisors [题意]给定f(n)=Σd|n gcd(d,n/d)的前缀和F(n),n=10^15. [算法]莫比乌斯反演 [题解]参考:任之洲数论函数.pdf 这个范围显然杜教筛也是做不了的,而且考虑直接化简f(n)也遇到了困难,所以考虑将前缀和的Σ一起化简. $$F(n)=\sum_{i=1}^{n}\sum_{d|i}(d,\frac{i}{d})$$ 这一步很常见的是第一重改为枚举倍数,但这样化简后面就推不下去了. 这道题必须最后转成$\sigma_0(n)$才…

题意:寻找这 1000 个数中相邻 13 个数相乘积最大的值 思路:首先想到的是暴力,但是还可以利用之前记录过的数值,什么意思呢?即在计算 2 - 14 后,再计算 3 - 15 时完全可以利用之前计算 2-14的值再除以 2 乘上 15 ,但是因为其中有 0 的存在需要改造一下,记录下之前出现的 0 的个数,当这连续13个数有 0 存在的时候,结果自然是 0 直接忽略,当没 0 的时候更新一下 maxN 即可. /****************************************…

Product of Array Except Self Given an array nums of n integers where n > 1, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i]. Example: Input: [1,2,3,4] Output: [24,12,8,6] Constraint: It's…

Comparing two numbers written in index form like 211 and 37 is not difficult, as any calculator would confirm that 211 = 2048 < 37 = 2187. However, confirming that 632382518061 > 519432525806 would be much more difficult, as both numbers contain ove…

The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832. Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product? 譯文: 觀察著1000個數字,通過…

这个我开始理解错了,算错了. 我以为是求连续5个数的最大值,结果,是连接5个数相乘的最大值. 英语不好,容易吃亏啊. Find the greatest product of five consecutive digits in the 1000-digit number. 7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891…

先粘实现代码,以后需要再慢慢补充思路 s = ''' 73167176531330624919225119674426574742355349194934 96983520312774506326239578318016984801869478851843 85861560789112949495459501737958331952853208805511 12540698747158523863050715693290963295227443043557 6689664895044524452…

本题来自 Project Euler 第8题:https://projecteuler.net/problem=8 # Project Euler: Problem 8: Largest product in a series # The four adjacent digits in the 1000-digit number # that have the greatest product are 9 × 9 × 8 × 9 = 5832. # Find the thirteen adjac…