题意: 215 = 32768,而32768的各位数字之和是 3 + 2 + 7 + 6 + 8 = 26. 21000的各位数字之和是多少? 思路:大数乘法,计算 210 × 100 可加速计算,每次超过1000进位 /************************************************************************* > File Name: euler016.c > Author: WArobot > Blog: http://www.…

215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26. What is the sum of the digits of the number 21000? 题目大意: 题目大意: 215 = 32768 并且其各位之和为 is 3 + 2 + 7 + 6 + 8 = 26. 21000 的各位数之和是多少? // (Problem 16)Power digit sum // Completed on Sun, 17 No…

>>> sum([int(i) for i in str(2**1000)]) 1366 >>>…

直接python搞过.没啥好办法.看了下别人做的,多数也是大数乘法搞过. 如果用大数做的话,c++写的话,fft优化大数乘法,然后快速幂一下就好了.…

基础的动态规划...数塔取数问题. 状态转移方程: dp[i][j] = num[i][j] + max(dp[i+1][j],dp[i+1][j+1]);…

题目 Square digit chains A number chain is created by continuously adding the square of the digits in a number to form a new number until it has been seen before. For example, 44 → 32 → 13 → 10 → 1 → 185 → 89 → 145 → 42 → 20 → 4 → 16 → 37 → 58 → 89 The…

Cube digit pairs Each of the six faces on a cube has a different digit (0 to 9) written on it; the same is done to a second cube. By placing the two cubes side-by-side in different positions we can form a variety of 2-digit numbers. For example, the…

Summation of primes Problem 10 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. The code resemble : import math limit = 2000000 crosslimit = int(math.sqrt(limit)) #sieve = [False] * limit sieve =…

题意须要注意的一点就是, 序列是从外层最小的那个位置顺时针转一圈得来的.而且要求10在内圈 所以,这题暴力的话,假定最上面那个点一定是第一个点,算下和更新下即可. #include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include <cstdlib> #include <ctime> #include <set> #i…

ORZ foreverlasting聚聚,QQ上问了他好久才会了这题(所以我们又聊了好久的Gal) 我们先来尝试推导一下\(S\)的性质,我们利用狄利克雷卷积来推: \[2^\omega=I\ast|\mu|\] 这个很好理解吧,考虑一下它的组合意义即可 然后两边同卷上\(I\)有: \[2^\omega \ast I=I\ast I\ast |\mu|=d\ast |\mu|\] 后面还是同样,考虑\(d\ast |\mu|\)的组合意义,一正一反的情况下其实就是\(d(n^2)\) 因此我们…