Codeforces 450(#257 (Div. 2) ) 解题报告

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
using namespace std;

typedef long long int64;

#define checkMax(a,b) a=max(a,b)

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
using namespace std;

typedef long long int64;

int main() {
int n, m, k;
cin >> n >> m >> k;
if (n - 1 + m - 1 < k) {
puts("-1");
return 0;
}
int64 ans = 0;
//    int cnt = 0;
for (int64 i = 1; i <= n; i++) {
//        ++cnt;
int64 r = n / (n / i);
i = r;
if (k - (r - 1) > m - 1)
continue;
int64 o = max(k - (r - 1) + 1, 1LL);
checkMax(ans, 1LL * (n / r) * (m / o));
//cout << " " << z << " " << t << " " << tt << endl;
}
//    cout << cnt << endl;
cout << ans << endl;
return 0;
}