符合条件的整数 循环节

题意

思路

很容易发现以7为一个循环节 那么先计算间距中有多少个循环节 再算下一开始的情况 因为右边是开区间 所以用需要摸7后需要大于1

code

#include <bits/stdc++.h>

using namespace std;

#define LL long long
#define ULL unsigned long long
#define mes(x, a) memset(x, a, sizeof(x));
#define sca(a) scanf("%d", &a)
#define lowbit(x) x&(-x)
#define mk make_pair
#define pb(x) push_back(x)
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
#define lson v << 1
#define rson v << 1 | 1
#define pii pair<int, int>

void read(int &x)
{
    x=0;
    int flag_read=1;
    char c=getchar();
    while(c<'0'||c>'9')
    {
        if(c=='-')
            flag_read=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9')
    {
        x=(x<<3)+(x<<1)+c-'0';
        c=getchar();
    }
    x *= flag_read;
}

void out(int x){
    if(x > 9){
        out(x / 10);
    }
    putchar(x % 10 + '0');
}

int main(){
    ios::sync_with_stdio(0);
    LL n , m;

    cin >> n >> m;

    n = 1LL << n;
    m = 1LL << m;

    LL res = m - n;

    res /= 7;

    if(n%7 == 1 && m%7 > 1){
        res ++ ;
    }

    cout << res << '\n';

    return 0;
}