codeforces 385C C. Bear and Prime Numbers(线性筛素数) 题目链接: codeforces 385C 题目大意: 给出n个数,数据范围107,给出m次查询,每次给出l,r求在l和r之间的素数的∑ki=0f(pi),f(pi)定义为n个数中能够整除pi的个数。 题目分析: 直接线性筛素数,记录每个数最大的素因数,然后统计对于每个素因数对应
intvis[maxm],cnt,prime[maxm],num[maxm]; longlongsum[maxm]; intmaxv; voidinit() { for(inti=0;i<=maxv;i++)isprime[i]=true; for(inti=2;i<=maxv;i++) { if(!isprime[i])continue; if(vis[i])num[i]+=vis[i]; prime[++cnt]=i; for(intj=i*2;j<=maxv;j+=i) { if(...
CodeForces - 385C Bear and Prime Numbers——素数筛法 在筛素数时计算每个数可以对应多少个题目中给定的数ai, 满足这个数是ai的因子, 然后预处理前缀和,O(1)完成查询 #include#include#include#includeusing namespace std;const int maxn = 1e6;const int maxm = 1e7 + 5;int n, m, a[maxn], l,...
Bear and Prime Numbers【素数筛】 题目链接:https://codeforc.es/problemset/problem/385/C 题目大意:给定nnn个数,定义f(p)f(p)f(p)为nnn个数中为ppp的倍数的个数,qqq次查询区间[l,r][l,r][l,r],计算∑pf(p)\sum_{p}f(p)∑pf(p),ppp为区间中的素数。 思路:由于nnn的数的值域不...
importjava.io.*;importjava.util.*;publicclassMain{staticInputReader in;staticPrintWriter out;publicstaticvoidmain(String[]args)throws IOException{//InputStream ins = new FileInputStream("E:\\rush.txt");InputStream ins=System.in;in=newInputReader(ins);out=newPrintWriter(System.out);//code start...
ACM测试2---C - Prime Number 有一种隐忍其实是蕴藏着的一种力量,有一种静默其实是惊天的告白。 Write a program which reads an integer n and prints the number of prime numbers which are less than or equal to n. A prime number is a natural number whi...2018...
for (q = 1,s = -1;q<=9;q++,s*=(-1)) Recusion(0,0,s,1); result += p; clock_t end = clock()-start; printf("0~1,000,000,000 , having %d prime numbers\n",result); printf("It used %d ms\n",(int)end); system("pause");}以上是 π(1000000000) 的程序在我的 2G物...
Codeforces 385 C Bear and Prime Numbers 题目链接~~> 做题感悟:这题属于想法题,比赛时直接做的 D 题。可是处理坐标处理的头晕眼花的结果到最后也没AC。 解题思路: 由于查询的时候仅仅考虑素数,so~我们仅仅考虑素数就能够,这就须要筛素数。我们能够在筛素数的同一时候把某个素数出现的倍数加上。输入的时候仅仅...
numbers less than 2 if (low <= 1) { ++low; continue; } // if low is a non-prime number, flag will be 1 for (i = 2; i <= low / 2; ++i) { if (low % i == 0) { flag = 1; break; } } if (flag == 0) printf("%d ", low); // to check prime for the next...
Program to Check Prime Number #include <stdio.h> int main() { int n, i, flag = 0; printf("Enter a positive integer: "); scanf("%d", &n); // 0 and 1 are not prime numbers // change flag to 1 for non-prime number if (n == 0 || n == 1) flag = 1; for (i = 2...