
注意longlong和check函数的写法
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long LL;
const int N = 200010;
int n;
LL m;
int a[N], b[N];
bool check(int mid)
{
for (int i = 0; i < n; i ++ )
{
if (a[i] + b[i] >= mid) m -= b[i];
if (a[i] + b[i] < mid) return false;
}
return true;
}
int main()
{
scanf("%d%lld", &n, &m);
for (int i = 0; i < n; i ++ ) scanf("%d", &a[i]);
for (int i = 0; i < n; i ++ ) scanf("%d", &b[i]);
int l = 0, r = 2 * n;
while (l < r)
{
int mid = l + r + 1 >> 1;
if (check(mid)) l = mid;
else r = mid - 1;
}
cout << r << endl;
return 0;
}