ZOJ 3629（找规律）

Treasure Hunt IV

Alice was very excited but unfortunately not all of the treasures are real, some are fake.

Now we know a treasure labled n is real if and only if [n/1] + [n/2] + ... + [n/k] + ... is even.

Now given 2 integers a and b, your job is to calculate how many real treasures are there.

Input

The input contains multiple cases, each case contains two integers a and b (0 <= a <= b <= 2⁶³-1) seperated by a single space.
Proceed to the end of file.

Output

Output the total number of real treasure.

Sample Input

0 2
0 10

Sample Output

1
6

额，找规律的题。看见 (0 <= a <= b <=
2⁶³-1) 时，就知道暴力会超时了，所以就找规律吧！

先写一个暴力的程序打表，这样的事以前也做过，一个循环节为197的规律题，打表只到100，还以为够了，结果那题没找到规律，以后再做这样的事的时候，先打表到10000再详谈！

#include<stdio.h>
int main()
{
    freopen("呵呵.txt","w",stdout);
    int i;
    for (i=0; i<=1000; i++)
    {
        int ans=0;
        for (int j=1; j<=i; j++)
        {
            ans+=i/j;
        }
        if (ans%2==0)
            printf("%d\t",i);
    }
    return 0;
}

[0^2,1^2)                   1

[2^2,3^2)                   5

[4^2,5^2)                   9

[6^2,7^2)                  13

[8^2,9^2)                  17

[10^2,11^2)              21

[12^2,13^2)              25

. . . .

. . . . . .

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