Sigma Function https://vjudge.net/contest/288520#problem/D Sigma function is an interesting function in Number Theory. It is denoted by the Greek letter Sigma (σ). This function actually denotes the sum of all divisors of a number. For example σ(24)…

一数三平方 有这样一个六位数,它本身是一个整数的平方,其高三位和低三位也分别是一个整数的平方,如225625=475*475,225=15*15,625=25*25;统计所有符合该条件的六位数 源代码: #include<stdio.h> #include<math.h> int ss(int value); int main(void) { long i,j,n1,n2,k; for(i=100000;i<=999999;i++) { j=(long)sqrt(i); if…

Leetcode 1577 数的平方等于两数乘积的方法数 题目 给你两个整数数组 nums1 和 nums2 ,请你返回根据以下规则形成的三元组的数目(类型 1 和类型 2 ): 类型 1:三元组 (i, j, k) ,如果$ nums1[i]2 == nums2[j] * nums2[k] 其中 0 <= i < nums1.length 且 0 <= j < k < nums2.length$ 类型 2:三元组 (i, j, k) ,如果 \(nums2[i]2 == n…

http://acm.hust.edu.cn/vjudge/contest/view.action?cid=109329#problem/C   题目在文末 题意:1~n (n:1~1012)中,因子和为偶数的有几个.题解: 因子和 Sum=(p1^0+p1^1….p1^e1)*(p2^0+p2^1…p2^e2)……(pn^0+…pn^en); = (p1^0+p1^1….p1^e1),(p2^0+p2^1…p2^e2),……(pn^0+…pn^en)中只要有一个是偶数,因子和sum就为偶数.所…

Sigma Function Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1336 Description Sigma function is an interesting function in Number Theory. It is denoted by the Greek letter Sigma (σ). This fu…

/** 题目:D - Sigma Function 链接:https://vjudge.net/contest/154246#problem/D 题意:求1~n内约数和为偶数的数的个数. 思路:一个数的约数和为那个数的每个素因子的等比和相乘.如题目所给公式就是等比和化简之后的式子. 那么要判断一个数约数和是否为偶数,可以通过观察它的各个素因子等比和来判断.如果存在某个素因子的等比和为偶数. 那么这个约数和肯定是偶数.否则为奇数. 素因子只有2是偶数,其他都是奇素数. 含素因子2的等比和一定为奇数…

题目链接:https://vjudge.net/problem/LightOJ-1336 1336 - Sigma Function    PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB Sigma function is an interesting function in Number Theory. It is denoted by the Greek letter Sigma (σ).…

Sigma function is an interesting function in Number Theory. It is denoted by the Greek letter Sigma (σ). This function actually denotes the sum of all divisors of a number. For example σ(24) = 1+2+3+4+6+8+12+24=60. Sigma of small numbers is easy to f…

链接: https://vjudge.net/problem/LightOJ-1336 题意: Sigma function is an interesting function in Number Theory. It is denoted by the Greek letter Sigma (σ). This function actually denotes the sum of all divisors of a number. For example σ(24) = 1+2+3+4+6…

http://lightoj.com/volume_showproblem.php?problem=1336 Sigma Function Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1336 Description Sigma function is an interesting function in Number Theor…