Urkupillit

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

#define M 1000000007

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    ll n, k;
    cin >> n >> k;

    vector<int> v(n);

    int upnum = n;
    int lownum = 1;

    for (int i = 0; i < n; ++i) {
        ll invs = n - i - 1;
        if (k >= invs) {
            v[i] = upnum--;
            k -= invs;
        } else {
            v[i] = lownum++;
        }
    }

    for (int x : v) {
        cout << x << " ";
    }
    cout << "\n";

    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED