Submission details
Task:Sort
Sender:jsesok
Submission time:2026-09-30 14:07:50 +0300
Language:C++ (C++23)
Status:READY
Result:0
Feedback
subtaskverdictscore
#10
#20
#30
#40
#50
#60
#70
Test results
testverdicttimesubtask
#10.00 s2, 6, 7details
#20.00 s1, 2, 3, 6, 7details
#30.00 s2, 6, 7details
#40.00 s1, 2, 3, 6, 7details
#50.00 s1, 2, 3, 6, 7details
#60.00 s1, 2, 3, 6, 7details
#70.00 s1, 2, 3, 6, 7details
#80.00 s1, 2, 3, 6, 7details
#90.00 s1, 2, 3, 6, 7details
#10ACCEPTED0.00 s1, 2, 3, 6, 7details
#110.00 s2, 6, 7details
#120.00 s2, 6, 7details
#130.00 s2, 6, 7details
#140.00 s2, 6, 7details
#150.00 s2, 6, 7details
#160.09 s3, 7details
#170.09 s3, 7details
#180.10 s3, 7details
#190.09 s3, 7details
#200.09 s3, 7details
#210.09 s3, 7details
#220.09 s3, 7details
#230.09 s3, 7details
#24--4, 7details
#25--4, 7details
#26--4, 7details
#27--4, 7details
#28--4, 7details
#29--4, 7details
#300.02 s5, 6, 7details
#310.01 s5, 6, 7details
#320.01 s5, 6, 7details
#330.07 s5, 6, 7details
#34ACCEPTED0.03 s5, 6, 7details
#350.06 s5, 6, 7details
#360.03 s6, 7details
#370.03 s6, 7details
#380.04 s6, 7details
#390.04 s6, 7details
#400.05 s6, 7details
#410.06 s6, 7details
#42--7details
#43--7details
#44--7details
#45--7details
#46--7details
#47--7details
#48--7details
#49--7details
#50--7details
#51--7details
#52ACCEPTED0.00 s1, 2, 3, 5, 6, 7details
#53ACCEPTED0.00 s1, 2, 3, 4, 5, 6, 7details
#54ACCEPTED0.00 s2, 5, 6, 7details
#550.00 s1, 2, 3, 4, 6, 7details
#560.00 s1, 2, 3, 6, 7details
#570.00 s6, 7details
#580.03 s3, 4, 7details
#590.03 s3, 7details
#600.00 s2, 6, 7details
#610.00 s2, 6, 7details
#620.00 s2, 6, 7details
#630.00 s2, 6, 7details
#640.00 s2, 6, 7details

Code

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, q;
    cin >> n >> q;

    vector<int> a(n);
    for (int &x : a) cin >> x;

    vector<int> sorted = a;
    sort(sorted.begin(), sorted.end());

    while (q--) {
        int p, s;
        cin >> p >> s;

        // Для 5-го сабтаска можно позволить O(n) на запрос.

        // Уже отсортирован?
        bool already = true;
        for (int i = 0; i < n; ++i) {
            if (a[i] != i + 1) {
                already = false;
                break;
            }
        }

        if (already) {
            cout << 0 << '\n';
            continue;
        }

        /*
            Сначала отдельно обрабатываем p+s <= n.
            Prefix и suffix не пересекаются.
        */
        if (p + s <= n) {
            bool possible = true;

            // Середину нельзя менять вообще.
            for (int i = p; i < n - s; ++i) {
                if (a[i] != i + 1) {
                    possible = false;
                    break;
                }
            }

            // В prefix должны находиться именно 1..p.
            if (possible) {
                for (int i = 0; i < p; ++i) {
                    if (a[i] > p) {
                        possible = false;
                        break;
                    }
                }
            }

            // В suffix должны находиться p+1..n
            // (с учётом неизменяемой середины проверка выше достаточна,
            // но оставим явную проверку).
            if (possible) {
                for (int i = n - s; i < n; ++i) {
                    if (a[i] <= n - s) {
                        possible = false;
                        break;
                    }
                }
            }

            if (!possible) {
                cout << -1 << '\n';
                continue;
            }

            int ans = 0;

            bool prefSorted = true;
            for (int i = 1; i < p; ++i) {
                if (a[i - 1] > a[i]) {
                    prefSorted = false;
                    break;
                }
            }

            bool suffSorted = true;
            for (int i = n - s + 1; i < n; ++i) {
                if (a[i - 1] > a[i]) {
                    suffSorted = false;
                    break;
                }
            }

            if (!prefSorted) ++ans;
            if (!suffSorted) ++ans;

            cout << ans << '\n';
            continue;
        }

        /*
            p+s > n.

            Разбиение:

               A       B       C
            [0,L)   [L,R)   [R,n)

            L = n-s
            R = p
            |B| = d = p+s-n
        */

        int L = n - s;
        int R = p;
        int d = R - L;

        /*
            Проверяем ответ 1.

            Одна prefix-sort работает iff всё после p
            уже находится на своих местах.

            Одна suffix-sort работает iff всё до n-s
            уже находится на своих местах.
        */

        bool oneP = true;
        for (int i = R; i < n; ++i) {
            if (a[i] != i + 1) {
                oneP = false;
                break;
            }
        }

        bool oneS = true;
        for (int i = 0; i < L; ++i) {
            if (a[i] != i + 1) {
                oneS = false;
                break;
            }
        }

        if (oneP || oneS) {
            cout << 1 << '\n';
            continue;
        }

        /*
            depthP:
            сколько P->S переходов требуется элементам,
            которые находятся слишком далеко слева.

            Элемент со значением x в A должен в итоге оказаться:
                x <= L       -> A
                L < x <= R   -> B
                x > R        -> C

            После каждого полного P,S "окно" доступных значений
            сдвигается на d.

            Для x в A:
                x > R + k*d
            означает, что требуется ещё один слой.
        */

        int needPS = 0;

        for (int i = 0; i < L; ++i) {
            int x = a[i];

            if (x > R) {
                int dist = x - R;

                int z = (dist + d - 1) / d;
                needPS = max(needPS, z);
            }
        }

        /*
            Аналогично справа.

            Если x <= L находится в C, ему нужно двигаться
            через S->P.

            Чем меньше x, тем больше слоёв.
        */

        int needSP = 0;

        for (int i = R; i < n; ++i) {
            int x = a[i];

            if (x <= L) {
                int dist = L - x + 1;

                int z = (dist + d - 1) / d;
                needSP = max(needSP, z);
            }
        }

        /*
            Теперь рассматриваем два варианта:

                P S P S ...
            или
                S P S P ...

            Но нужно также учесть локальную неотсортированность
            крайних частей.
        */

        bool needP = false;
        for (int i = 1; i < R; ++i) {
            if (a[i - 1] > a[i]) {
                needP = true;
                break;
            }
        }

        bool needS = false;
        for (int i = L + 1; i < n; ++i) {
            if (a[i - 1] > a[i]) {
                needS = true;
                break;
            }
        }

        int ans = INT_MAX;

        /*
            Начинаем с P.

            За t операций:
              количество P = (t+1)/2
              количество S = t/2

            Число переходов P->S = floor(t/2).
            Число переходов S->P = floor((t-1)/2).
        */

        for (int extra = 0; extra <= 4; ++extra) {
            int base = 2 * max(needPS, needSP) + extra;

            // P-first
            {
                int t = base;

                int cntP = (t + 1) / 2;
                int cntS = t / 2;

                int ps = t / 2;
                int sp = (t - 1) / 2;

                if (ps >= needPS &&
                    sp >= needSP &&
                    (!needP || cntP > 0) &&
                    (!needS || cntS > 0)) {
                    ans = min(ans, t);
                }
            }

            // S-first
            {
                int t = base;

                int cntS = (t + 1) / 2;
                int cntP = t / 2;

                int sp = t / 2;
                int ps = (t - 1) / 2;

                if (ps >= needPS &&
                    sp >= needSP &&
                    (!needP || cntP > 0) &&
                    (!needS || cntS > 0)) {
                    ans = min(ans, t);
                }
            }
        }

        cout << ans << '\n';
    }
}

Test details

Test 1

Subtask: 2, 6, 7

Verdict:

input
6 3
3 1 4 1 5 9
4 1
3 3
2 5

correct output
1
-1
2

user output
1
-1
3

Feedback: Incorrect character on line 3 col 1: expected "2", got "3"

Test 2

Subtask: 1, 2, 3, 6, 7

Verdict:

input
2 1
548813503 548813503
1 1

correct output
0

user output
-1

Feedback: Incorrect character on line 1 col 1: expected "0", got "-1"

Test 3

Subtask: 2, 6, 7

Verdict:

input
1 1
417021999
1 1

correct output
0

user output
1

Feedback: Incorrect character on line 1 col 1: expected "0", got "1"

Test 4

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
20751947 20751947 20751947 494...

correct output
-1
-1
1
1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 3 col 1: expected "1", got "-1"

Test 5

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
12780811 19475241 19475241 683...

correct output
0
0
0
0
0
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "-1"

Test 6

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
14574963 14574963 14574963 864...

correct output
0
0
0
0
0
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "-1"

Test 7

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
237541216 237541216 35036522 6...

correct output
-1
-1
-1
2
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 4 col 1: expected "2", got "-1"

Test 8

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
319425549 513116712 539199939 ...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 6 col 1: expected "1", got "-1"

Test 9

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
54363219 54363219 110986323 11...

correct output
0
0
0
0
0
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "-1"

Test 10

Subtask: 1, 2, 3, 6, 7

Verdict: ACCEPTED

input
10 5
55687086 550701455 326656159 5...

correct output
-1
-1
-1
-1
-1

user output
-1
-1
-1
-1
-1

Test 11

Subtask: 2, 6, 7

Verdict:

input
10 10
35889584 588130796 815837475 8...

correct output
-1
-1
1
1
1
...

user output
-1
-1
-1
196043596
-1
...

Feedback: Incorrect character on line 3 col 1: expected "1", got "-1"

Test 12

Subtask: 2, 6, 7

Verdict:

input
10 10
679842175 48724877 720966351 6...

correct output
2
3
2
1
1
...

user output
339921086
1598543724
720966344
1
1
...

Feedback: Incorrect character on line 1 col 1: expected "2", got "339921086"

Test 13

Subtask: 2, 6, 7

Verdict:

input
10 10
893310183 811950921 338863962 ...

correct output
2
1
1
2
5
...

user output
255231480
1
1
446655090
1786620358
...

Feedback: Incorrect character on line 1 col 2: expected "2", got "255231480"

Test 14

Subtask: 2, 6, 7

Verdict:

input
10 10
221045363 282395847 441913686 ...

correct output
0
0
0
0
0
...

user output
63155816
-1
1
1
-1
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "63155816"

Test 15

Subtask: 2, 6, 7

Verdict:

input
10 10
509019662 983949268 960017302 ...

correct output
3
-1
3
3
3
...

user output
655966176
-1
655966176
399946916
999867286
...

Feedback: Incorrect character on line 1 col 1: expected "3", got "655966176"

Test 16

Subtask: 3, 7

Verdict:

input
200000 200000
2277053 2277053 2277053 227705...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 46 col 1: expected "2", got "-1"

Test 17

Subtask: 3, 7

Verdict:

input
200000 200000
6767 16596 16596 27202 37272 4...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 6 col 1: expected "1", got "-1"

Test 18

Subtask: 3, 7

Verdict:

input
200000 200000
5393 5910 9099 15755 15755 164...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 11 col 1: expected "2", got "-1"

Test 19

Subtask: 3, 7

Verdict:

input
200000 200000
3779 4629 8999 10468 22605 227...

correct output
-1
1
2
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 2 col 1: expected "1", got "-1"

Test 20

Subtask: 3, 7

Verdict:

input
200000 200000
878 2791 10849 11861 13405 239...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 13 col 1: expected "2", got "-1"

Test 21

Subtask: 3, 7

Verdict:

input
200000 200000
430 1479 1992 2829 7152 14093 ...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 98 col 1: expected "2", got "-1"

Test 22

Subtask: 3, 7

Verdict:

input
199997 200000
2733 10526 13882 14035 14689 3...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 20 col 1: expected "1", got "-1"

Test 23

Subtask: 3, 7

Verdict:

input
200000 200000
12345 13538 15407 18490 18984 ...

correct output
0
0
0
0
0
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "-1"

Test 24

Subtask: 4, 7

Verdict:

input
200000 200000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
-1
1
-1
-1
-1
...

user output
(empty)

Test 25

Subtask: 4, 7

Verdict:

input
200000 200000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
1
-1
1
-1
1
...

user output
(empty)

Test 26

Subtask: 4, 7

Verdict:

input
200000 200000
2 2 1 1 2 1 2 1 2 2 2 1 1 1 2 ...

correct output
4
3
2
2
6
...

user output
(empty)

Test 27

Subtask: 4, 7

Verdict:

input
200000 200000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
0
0
0
0
0
...

user output
(empty)

Test 28

Subtask: 4, 7

Verdict:

input
200000 200000
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 ...

correct output
8513
1099
35939
9299
19597
...

user output
(empty)

Test 29

Subtask: 4, 7

Verdict:

input
200000 200000
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 ...

correct output
178345
169257
62115
96143
64796
...

user output
(empty)

Test 30

Subtask: 5, 6, 7

Verdict:

input
5000 5000
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
1
1
-1
1
-1
...

user output
1
1
-1
1
-1
...

Feedback: Incorrect character on line 11 col 1: expected "3", got "10"

Test 31

Subtask: 5, 6, 7

Verdict:

input
5000 5000
1 2 3 4 5 6 7 8 9 72 145 47 19...

correct output
-1
2
-1
2
-1
...

user output
-1
2
-1
2
-1
...

Feedback: Incorrect character on line 14 col 1: expected "3", got "4"

Test 32

Subtask: 5, 6, 7

Verdict:

input
4999 5000
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
-1
2
-1
-1
-1
...

user output
-1
2
-1
-1
-1
...

Feedback: Incorrect character on line 1036 col 1: expected "3", got "18"

Test 33

Subtask: 5, 6, 7

Verdict:

input
5000 5000
4033 4368 3086 3208 4313 388 8...

correct output
3
3
3
3
11
...

user output
5
3
3
3
30
...

Feedback: Incorrect character on line 1 col 1: expected "3", got "5"

Test 34

Subtask: 5, 6, 7

Verdict: ACCEPTED

input
5000 5000
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
0
0
0
0
0
...

user output
0
0
0
0
0
...

Test 35

Subtask: 5, 6, 7

Verdict:

input
5000 5000
5000 4999 4998 4997 4996 4995 ...

correct output
2039
1910
-1
687
673
...

user output
7926
8062
-1
4306
1308
...

Feedback: Incorrect character on line 1 col 1: expected "2039", got "7926"

Test 36

Subtask: 6, 7

Verdict:

input
5000 5000
202010 457852 826471 926337 10...

correct output
-1
-1
2
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 3 col 1: expected "2", got "-1"

Test 37

Subtask: 6, 7

Verdict:

input
5000 5000
190583 326486 431922 462939 72...

correct output
-1
-1
-1
-1
2
...

user output
-1
-1
-1
-1
229134
...

Feedback: Incorrect character on line 5 col 2: expected "2", got "229134"

Test 38

Subtask: 6, 7

Verdict:

input
5000 5000
821998255 400550008 71790232 5...

correct output
5
3
3
2
5
...

user output
2941090
2091984
1474884
469028
9008756
...

Feedback: Incorrect character on line 1 col 1: expected "5", got "2941090"

Test 39

Subtask: 6, 7

Verdict:

input
5000 5000
266174928 446601941 191252234 ...

correct output
3
3
414
4
3
...

user output
781760
690756
333290006
2971378
416424
...

Feedback: Incorrect character on line 1 col 1: expected "3", got "781760"

Test 40

Subtask: 6, 7

Verdict:

input
5000 5000
11621 243915 243915 949123 137...

correct output
0
0
0
0
0
...

user output
2290800
357822666
28720962
-1
68452
...

Feedback: Incorrect character on line 1 col 1: expected "0", got "2290800"

Test 41

Subtask: 6, 7

Verdict:

input
5000 5000
999767052 998555066 997822810 ...

correct output
919
459
505
833
809
...

user output
499881982
499881492
666510854
499882662
1999524918
...

Feedback: Incorrect character on line 1 col 1: expected "919", got "499881982"

Test 42

Subtask: 7

Verdict:

input
200000 200000
478025 478025 478025 478025 47...

correct output
-1
-1
2
2
2
...

user output
(empty)

Test 43

Subtask: 7

Verdict:

input
200000 200000
1810 2088 3022 3097 7459 7943 ...

correct output
2
-1
-1
2
-1
...

user output
(empty)

Test 44

Subtask: 7

Verdict:

input
199531 200000
11328 26391 30353 37063 44412 ...

correct output
-1
2
-1
2
2
...

user output
(empty)

Test 45

Subtask: 7

Verdict:

input
200000 200000
106738201 369187074 412614650 ...

correct output
2
12
3
19
3
...

user output
(empty)

Test 46

Subtask: 7

Verdict:

input
200000 200000
670611290 43427363 8475380 309...

correct output
3
5
3
3
3
...

user output
(empty)

Test 47

Subtask: 7

Verdict:

input
200000 200000
907542569 504758282 948727805 ...

correct output
3
33
3
3
3
...

user output
(empty)

Test 48

Subtask: 7

Verdict:

input
200000 200000
487056731 460461648 142698485 ...

correct output
3
3
3
3
3
...

user output
(empty)

Test 49

Subtask: 7

Verdict:

input
200000 200000
12772 23236 23236 23236 41149 ...

correct output
0
0
0
0
0
...

user output
(empty)

Test 50

Subtask: 7

Verdict:

input
200000 200000
999993539 999993361 999993361 ...

correct output
125375
16687
-1
84781
46147
...

user output
(empty)

Test 51

Subtask: 7

Verdict:

input
200000 200000
999993539 999993361 999993361 ...

correct output
94788
177608
95881
56377
179957
...

user output
(empty)

Test 52

Subtask: 1, 2, 3, 5, 6, 7

Verdict: ACCEPTED

input
5 1
2 1 3 5 4
2 2

correct output
2

user output
2

Test 53

Subtask: 1, 2, 3, 4, 5, 6, 7

Verdict: ACCEPTED

input
2 1
1 2
1 1

correct output
0

user output
0

Test 54

Subtask: 2, 5, 6, 7

Verdict: ACCEPTED

input
4 1
2 1 4 3
3 2

correct output
2

user output
2

Test 55

Subtask: 1, 2, 3, 4, 6, 7

Verdict:

input
10 10
1 1 1 1 2 2 1 1 2 2
7 1
2 6
4 5
...

correct output
-1
1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 2 col 1: expected "1", got "-1"

Test 56

Subtask: 1, 2, 3, 6, 7

Verdict:

input
10 10
181777772 181777772 181777772 ...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 10 col 1: expected "1", got "-1"

Test 57

Subtask: 6, 7

Verdict:

input
100 10
92800811 524548163 939127795 9...

correct output
-1
-1
3
-1
3
...

user output
-1
-1
35438784
-1
31220014
...

Feedback: Incorrect character on line 3 col 2: expected "3", got "35438784"

Test 58

Subtask: 3, 4, 7

Verdict:

input
100 100000
2 2 2 1 2 2 2 2 1 2 1 1 1 2 2 ...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 1401 col 1: expected "1", got "-1"

Test 59

Subtask: 3, 7

Verdict:

input
100 100000
172695325 172695325 172695325 ...

correct output
-1
-1
-1
-1
-1
...

user output
-1
-1
-1
-1
-1
...

Feedback: Incorrect character on line 417 col 1: expected "1", got "-1"

Test 60

Subtask: 2, 6, 7

Verdict:

input
4 10
869194539 239439572 968540665 ...

correct output
-1
2
-1
-1
-1
...

user output
-1
1738389072
-1
-1
-1
...

Feedback: Incorrect character on line 2 col 1: expected "2", got "1738389072"

Test 61

Subtask: 2, 6, 7

Verdict:

input
10 10
55366041 112170735 112170735 5...

correct output
-1
-1
2
1
1
...

user output
-1
-1
1288016406
55366038
1
...

Feedback: Incorrect character on line 3 col 1: expected "2", got "1288016406"

Test 62

Subtask: 2, 6, 7

Verdict:

input
10 10
156018639 156018639 445832758 ...

correct output
-1
1
-1
-1
2
...

user output
-1
1
-1
-1
297221834
...

Feedback: Incorrect character on line 5 col 2: expected "2", got "297221834"

Test 63

Subtask: 2, 6, 7

Verdict:

input
10 10
702507512 702507512 892090406 ...

correct output
-1
2
-1
2
2
...

user output
-1
446045200
-1
594726932
234169168
...

Feedback: Incorrect character on line 2 col 1: expected "2", got "446045200"

Test 64

Subtask: 2, 6, 7

Verdict:

input
10 10
720324490 720324490 720324490 ...

correct output
-1
2
2
1
-1
...

user output
-1
720324484
360162244
1
-1
...

Feedback: Incorrect character on line 2 col 1: expected "2", got "720324484"