mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-12-03 19:56:26 +00:00
50 lines
1.0 KiB
C++
50 lines
1.0 KiB
C++
|
#include <bits/stdc++.h>
|
||
|
|
||
|
using namespace std;
|
||
|
|
||
|
int t, k;
|
||
|
long long x, ans;
|
||
|
|
||
|
inline long long calc(long long d) {
|
||
|
return (d + 1) * d / 2;
|
||
|
}
|
||
|
|
||
|
inline long long calc2(long long d) {
|
||
|
return (k * 2 - d + 1) * d / 2;
|
||
|
}
|
||
|
|
||
|
int main() {
|
||
|
cin >> t;
|
||
|
while (t--) {
|
||
|
cin >> k >> x;
|
||
|
long long l = 0, r = k;
|
||
|
while (l < r) {
|
||
|
int mid = l + r + 1 >> 1;
|
||
|
if (calc(mid) <= x) {
|
||
|
l = mid;
|
||
|
} else {
|
||
|
r = mid - 1;
|
||
|
}
|
||
|
}
|
||
|
if (r < k) {
|
||
|
ans = r + (calc(r) < x);
|
||
|
cout << min(ans, k * 2ll - 1) << endl;
|
||
|
continue;
|
||
|
}
|
||
|
x -= (k - 1ll) * k / 2ll;
|
||
|
l = 0;
|
||
|
r = k;
|
||
|
while (l < r) {
|
||
|
int mid = l + r + 1 >> 1;
|
||
|
if (calc2(mid) <= x) {
|
||
|
l = mid;
|
||
|
} else {
|
||
|
r = mid - 1;
|
||
|
}
|
||
|
}
|
||
|
ans = (r + k - 1 + (calc2(r) < x));
|
||
|
cout << min(ans, k * 2ll - 1) << endl;
|
||
|
}
|
||
|
return 0;
|
||
|
}
|