Prime Generator（spoj）

时间：2014-12-20 16:45:38 收藏：0 阅读：179

原题：

Prime Generator

Problem code: PRIME1

Peter wants to generate some prime numbers for his cryptosystem. Help him! Your task is to generate all prime numbers between two given numbers!

Input

The input begins with the number t of test cases in a single line (t<=10). In each of the next t lines there are two numbers m and n (1 <= m <= n <= 1000000000, n-m<=100000) separated by a space.

Output

For every test case print all prime numbers p such that m <= p <= n, one number per line, test cases separated by an empty line.

Example

Input:
2
1 10
3 5

Output:
2
3
5
7

3
5
这题太水，我也不知道为什么，ac率会这么低，我用最简单的方法竟然过了，本来以为要用到筛法呢，用兴趣的可以看看晒法。不说了，直接上代码：

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<cmath>
 4 using namespace std;
 5 
 6 int isPrime(int n)
 7 {
 8    if(n<=1) 
 9        {
10            return false;
11     }
12    if(n==2)
13        {
14            return true;
15        }
16    else 
17        {
18            for(int i=2;    i<=sqrt(n);    i++)
19            {
20                if(n%i==0)
21                   return false;
22            }
23            return true;
24        }    
25 }
26 
27 int main() 
28 {
29     int t; 
30     int m,n;
31     scanf("%d",&t);
32     while(t--)
33     {
34         scanf("%d%d",&m,&n);
35         for(int j=m;    j<=n;    j++)
36         {
37             if(isPrime(j))
38             printf("%d\n",j);
39         }
40         printf("\n");
41     }
42     return 0;
43 }