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light oj 1007 - Mathematically Hard

with splay b- num def can efi input log

Mathematically some problems look hard. But with the help of the computer, some problems can be easily solvable.

In this problem, you will be given two integers a and b. You have to find the summation of the scores of the numbers from a to b (inclusive). The score of a number is defined as the following function.

score (x) = n2, where n is the number of relatively prime numbers with x, which are smaller than x

For example,

For 6, the relatively prime numbers with 6 are 1 and 5. So, score (6) = 22 = 4.

For 8, the relatively prime numbers with 8 are 1, 3, 5 and 7. So, score (8) = 42 = 16.

Now you have to solve this task.

Input

Input starts with an integer T (≤ 105), denoting the number of test cases.

Each case will contain two integers a and b (2 ≤ a ≤ b ≤ 5 * 106).

Output

For each case, print the case number and the summation of all the scores from a to b.

Sample Input

Output for Sample Input

3

6 6

8 8

2 20

Case 1: 4

Case 2: 16

Case 3: 1237

Note

Euler‘s totient function applied to a positive integer n is defined to be the number of positive integers less than or equal to n that are relatively prime to n. is read "phi of n."

Given the general prime factorization of , one can compute using the formula

題目大意:求出a到b之間所有數本身與小於其本身互素的數的個數的平方和(歐拉函數打表,區間平方和打表)。

題不是很難卡在了數據類型上,錯了好幾次(反思)。需要用到unsigned long long

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#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#define LL unsigned long long
using namespace std;
int phi[5000005]={0};
LL sum[5000005]={0};
void inin1()
{
    for(int i=2; i<5000002; i++)
    {
        if(phi[i]==0)
        for(int j=i; j<=5000002; j+=i)
        {
            if(phi[j]==0)phi[j]=j;
            phi[j]=phi[j]/i*(i-1);
        }
    }
}
void inin2()
{
    for(int i=2; i<=5000000; i++)
        sum[i]=sum[i-1]+(LL)phi[i]*(LL)phi[i];
}
int main()
{
    inin1();
    inin2();
    int T, t=1;
    scanf("%d", &T);
    while(T--)
    {
        int a, b;
        scanf("%d%d", &a, &b);
        printf("Case %d: %llu\n", t++, sum[b]-sum[a-1]);
    }
    return 0;
}
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light oj 1007 - Mathematically Hard