[SCOI2009]生日快乐

#include <cstdio>
#include <iostream>
using namespace std;
double t;
int x, y, n;
inline double DFS (double a, double b, int n)
{
double s = 2e18;
if (n == 1)
return max (a, b) / min (a, b);
for (int i = 1, j = n - 1; i <= j; i ++, j --)
{
s = min (s, max (DFS (a, t / a * i, i), DFS (a, t / a * j, j)));
s = min (s, max (DFS (t / b * i, b, i), DFS (t / b * j, b, j)));
}
return s;
}
int main ()
{
scanf ("%d%d%d", &x, &y, &n);
t = double (x) * y / n;
printf ("%.6lf", DFS (x, y, n));
return 0;
}