bzoj1053: [HAOI2007]反素数ant

#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
#define MAXP 10
long long n;
int p[MAXP] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29};
struct qtype
{
long long data;
int ct[MAXP];
qtype(long long _data, int *_ct)
: data(_data)
{
memcpy(ct, _ct, sizeof(ct));
}
bool operator> (const qtype &x)const
{
return data > x.data;
}
};
int ct[MAXP] = {0};
priority_queue<qtype, vector<qtype>, greater<qtype> > q;
int main()
{
scanf("%lld", &n);
q.push(qtype(1, ct));
long long ans = 1, mct = 0, last = 0;
while (!q.empty())
{
long long a = q.top().data;
memcpy(ct, q.top().ct, sizeof(ct));
q.pop();
if (a == last)
continue;
last = a;
long long t = 1;
for (int i = 0; i < MAXP; ++i)
t *= ct[i] + 1;
for (int i = 0; i < MAXP && a * p[i] <= n; ++i)
{
if (i && ct[i] + 1 > ct[i - 1])
continue;
++ct[i];
q.push(qtype(a * p[i], ct));
--ct[i];
}
if (t > mct)
mct = t, ans = a;
}
printf("%lld\n", ans);
return 0;
}