224
汽車大全
一百萬以內的素數
#include <iostream>
#include <vector>
using namespace std;
#define MAX 1000000
long s[MAX+1];
void init()//構造一個100萬以內的素數表
{
int i, j;
for (i = 2; i <= MAX; i++)
{
s[i] = 1;
}
s[0] = s[1] = 0; //0和1肯定不是素數
for (i = 2; i <= MAX; i++)
{
if (s[i] == 1)
{
for (j = 2 * i; j <= MAX; j += i)
s[j] = 0;
}
}
}
int main()
{
init();//構造一個100萬以內的素數表
long a, b;
int tmp = 0;
int i, j;
vector<int> vec;
while (cin >> a >> b)
{
for (i = a; i <= b; i++)
{
if (s[i] == 1)
tmp++;
}
vec.push_back(tmp);
tmp = 0;
}
i = 1;
for (vector<int>::iterator it = vec.begin(); it != vec.end(); it++)
{
cout << "Case " << i++ << ":" << endl;
cout << *it << endl;
}
//system("pause");
return 0;
}
最後更新：2017-04-02 15:15:28