HDU
素数判定
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 189701 Accepted Submission(s): 66890
Problem Description
对于表达式n^2+n+41,当n在(x,y)范围内取整数值时(包括x,y)(-39<=x<y<=50),判定该表达式的值是否都为素数。
Input
输入数据有多组,每组占一行,由两个整数x,y组成,当x=0,y=0时,表示输入结束,该行不做处理。
Output
对于每个给定范围内的取值,如果表达式的值都为素数,则输出"OK",否则请输出“Sorry”,每组输出占一行。
Sample Input
0 1
0 0
Sample Output
OK
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
int main(int argc, char **argv)
{
int x, y;
while (~scanf("%d%d",&x,&y))
{
if (x == 0 && y == 0)
break;
int flag = 1;//设立检测变量
for (int i = x; i <= y; i++)
{
int n = i * i + i + 41;
for (int j = 2; j <= (int)sqrt(n); j++)//素数判定的初步优化
{
if (n%j == 0)
{
flag = 0;
break;
}
}
}
if (flag == 0)
printf("Sorry\n");
else
printf("OK\n");
}
system("pause");
}