BZOJ1853: [Scoi2010]幸运数字(容斥原理)

// luogu-judger-enable-o2
// luogu-judger-enable-o2
// luogu-judger-enable-o2
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<stack>
#include<vector>
#include<cstring>
#define int long long 
//#define int long long
using namespace std;
const int MAXN = 1e6;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < '0' || c > '9'){if(c == '-') f = -1; c = getchar();}
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}
int Mx = 10000000000LL;
vector<int> a;
int flag[MAXN], vis[MAXN], b[MAXN], out, cnt;
void Pre(int now) {
    if(now >= Mx) return ;
    a.push_back(now);
    Pre(now * 10 + 6); Pre(now * 10 + 8);
}
void dfs(int x, int opt, int l, int r, int pre) {
    if(x > r) return ;
    //printf("%I64d\n", out);
    out += opt * (r / x - l / x);
    for(int i = pre + 1; i <= cnt; i++) {
        int g = __gcd(x, b[i]);
        if((double) (x / g) * b[i] > (double)r) return;
        dfs(x / g * b[i], opt * -1, l, r, i);
    }
}
int solve(int l, int r) {
    out = 0;
    for(int i = 1; i <= cnt; i++)
        dfs(b[i], 1, l, r, i);
    return out;
}
main() {
    Pre(6);
    Pre(8);
    //printf("%d", a.size()); 
    for(int i = 0; i < a.size(); i++) 
        for(int j = 0; j < a.size(); j++)
            if((i != j) && (a[j] > a[i]) && (a[j] % a[i] == 0)) flag[j] = 1;
    //printf("%d\n", si);
    for(int i = 0; i < a.size(); i++)
        if(!flag[i]) b[++cnt] = a[i]; 
    sort(b + 1, b + cnt + 1, greater<int>());
    //for(int i = 1; i <= cnt; i++)
    //-    printf("%d\n", cnt);
    int a = read(), b = read();
    printf("%lld", solve(a - 1, b) + 1);
    return 0;
}
/*
2 10000000000
*/