二分判断
#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
typedef pair<int, int> PII;
const int N = 1e7;
PII a[N];
int n, k;
bool check(int x)
{
int ans = 0;
for(int i = 1; i <= n; i ++ )
ans += (a[i].x / x) * (a[i].y / x);
return ans >= k;
}
int main()
{
cin >> n >> k;
for(int i = 1; i <= n; i ++ )
scanf("%d%d", &a[i].x, &a[i].y);
int l = 0, r = 1e5;
while(l < r)
{
int mid = l + r + 1 >> 1;
if(check(mid)) l = mid;
else r = mid - 1;
}
cout << l;
}