Submission details
Task:Huippualkio
Sender:jlaire
Submission time:2025-11-07 18:44:45 +0200
Language:C++ (C++17)
Status:READY
Result:0
Feedback
groupverdictscore
#10
#20
#30
Test results
testverdicttimegroup
#1ACCEPTED0.01 s1, 2, 3details
#2ACCEPTED0.02 s1, 2, 3details
#3ACCEPTED0.01 s1, 2, 3details
#4ACCEPTED0.01 s1, 2, 3details
#5ACCEPTED0.01 s1, 2, 3details
#6ACCEPTED0.02 s1, 2, 3details
#7ACCEPTED0.02 s1, 2, 3details
#80.02 s1, 2, 3details
#9ACCEPTED0.02 s2, 3details
#10ACCEPTED0.01 s2, 3details
#11ACCEPTED0.02 s2, 3details
#12ACCEPTED0.02 s2, 3details
#13ACCEPTED0.01 s2, 3details
#140.02 s2, 3details
#150.18 s3details
#160.18 s3details
#170.25 s3details
#180.47 s3details
#190.37 s3details
#200.37 s3details
#21ACCEPTED0.02 s1, 2, 3details
#22ACCEPTED0.02 s2, 3details
#230.40 s3details
#24ACCEPTED0.01 s1, 2, 3details
#25ACCEPTED0.01 s1, 2, 3details
#26ACCEPTED0.01 s1, 2, 3details
#27ACCEPTED0.02 s1, 2, 3details
#28ACCEPTED0.01 s1, 2, 3details
#29ACCEPTED0.01 s1, 2, 3details
#30ACCEPTED0.01 s1, 2, 3details
#31ACCEPTED0.01 s1, 2, 3details

Code

#include <algorithm>
#include <functional>
#include <iostream>
#include <map>
using namespace std;
using Q = function<int(int)>;

map<int,int> CACHE;
int query_io(int pos) {
    if (CACHE.count(pos)) return CACHE[pos];
    cout << "? " << pos << endl;
    int x; cin>>x;
    return CACHE[pos]=x;
}

bool lmax(int pos, Q q) {
    return q(pos) >= max(q(pos-1), q(pos+1));
}

int solve_brute(int L, int R, Q q) {
    for (int i=L+1; i<R; i++)
        if (lmax(i,q)) return i;
    return lmax(L,q) ? L : R;
}

int solve(int L, int R, Q q) {
    if (L==R) {
        return L;
    }
    if (R-L<=5) {
        return solve_brute(L,R,q);
    }
    // L ... A ... B ... R
    int A = L + (R-L)/3;
    int B = A + (R-L)/3;
    if (q(A)>=max(q(L),q(B))) {
        return solve(L,B,q);
    }
    return solve(A,R,q);
}

int main() {
    int n; cin>>n;
    int ans = solve(1, n, [=](int pos) {
        if (pos<=0 || pos>n) return -1;
        return query_io(pos);
    });
    cout << "! " << ans << endl;
}

Test details

Test 1 (public)

Group: 1, 2, 3

Verdict: ACCEPTED

input
8
5 2 4 1 3 3 2 4

correct output
(empty)

user output
8
? 3
4
? 5
3
...

Error:
1 1 100 0

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

input
1
1

correct output
(empty)

user output
1
! 1

Error:
1 1 100 0

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
(empty)

user output
50
? 17
1
? 33
1
...

Error:
1 1 100 0

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
2 1 2 2 2 2 1 1 1 1 2 1 1 2 2 ...

correct output
(empty)

user output
50
? 17
1
? 33
1
...

Error:
1 1 100 0

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
657 448 315 782 966 983 560 32...

correct output
(empty)

user output
50
? 17
451
? 33
88
...

Error:
1 1 100 0

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
541463939 624015614 406717194 ...

correct output
(empty)

user output
50
? 17
574417829
? 33
688380735
...

Error:
1 1 100 0

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
(empty)

user output
50
? 17
17
? 33
33
...

Error:
1 1 100 0

Test 8

Group: 1, 2, 3

Verdict:

input
50
50 49 48 47 46 45 44 43 42 41 ...

correct output
(empty)

user output
50
? 17
34
? 33
18
...

Error:
1 1 101 0

Test 9

Group: 2, 3

Verdict: ACCEPTED

input
100
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
(empty)

user output
100
? 34
1
? 67
1
...

Error:
1 1 100 0

Test 10

Group: 2, 3

Verdict: ACCEPTED

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

correct output
(empty)

user output
100
? 34
1
? 67
2
...

Error:
1 1 100 0

Test 11

Group: 2, 3

Verdict: ACCEPTED

input
100
401 388 765 398 183 79 268 339...

correct output
(empty)

user output
100
? 34
955
? 67
930
...

Error:
1 1 100 0

Test 12

Group: 2, 3

Verdict: ACCEPTED

input
100
34030354 571736161 659501910 9...

correct output
(empty)

user output
100
? 34
685097645
? 67
337502849
...

Error:
1 1 100 0

Test 13

Group: 2, 3

Verdict: ACCEPTED

input
100
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
(empty)

user output
100
? 34
34
? 67
67
...

Error:
1 1 100 0

Test 14

Group: 2, 3

Verdict:

input
100
100 99 98 97 96 95 94 93 92 91...

correct output
(empty)

user output
100
? 34
67
? 67
34
...

Error:
1 1 101 0

Test 15

Group: 3

Verdict:

input
1000000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
(empty)

user output
1000000
? 333334
1
? 666667
1
...

Error:
1 1 101 0

Test 16

Group: 3

Verdict:

input
1000000
2 1 1 2 2 2 2 1 2 1 1 1 1 1 1 ...

correct output
(empty)

user output
1000000
? 333334
1
? 666667
2
...

Error:
1 1 101 0

Test 17

Group: 3

Verdict:

input
1000000
338 877 986 388 699 868 559 99...

correct output
(empty)

user output
1000000
? 333334
589
? 666667
935
...

Error:
1 1 101 0

Test 18

Group: 3

Verdict:

input
1000000
301892461 304390263 250772451 ...

correct output
(empty)

user output
1000000
? 333334
381341657
? 666667
683925354
...

Error:
1 1 101 0

Test 19

Group: 3

Verdict:

input
1000000
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
(empty)

user output
1000000
? 333334
333334
? 666667
666667
...

Error:
1 1 101 0

Test 20

Group: 3

Verdict:

input
1000000
1000000 999999 999998 999997 9...

correct output
(empty)

user output
1000000
? 333334
666667
? 666667
333334
...

Error:
1 1 101 0

Test 21

Group: 1, 2, 3

Verdict: ACCEPTED

input
50
1000000 1000001 1000002 100000...

correct output
(empty)

user output
50
? 17
1000016
? 33
1000028
...

Error:
1 1 100 0

Test 22

Group: 2, 3

Verdict: ACCEPTED

input
100
1000000 1000001 1000002 100000...

correct output
(empty)

user output
100
? 34
1000025
? 67
999992
...

Error:
1 1 100 0

Test 23

Group: 3

Verdict:

input
1000000
1000000 1000001 1000002 100000...

correct output
(empty)

user output
1000000
? 333334
1333333
? 666667
1081158
...

Error:
1 1 101 0

Test 24

Group: 1, 2, 3

Verdict: ACCEPTED

input
1
1000000000

correct output
(empty)

user output
1
! 1

Error:
1 1 100 0

Test 25

Group: 1, 2, 3

Verdict: ACCEPTED

input
2
1 1

correct output
(empty)

user output
2
? 1
1
? 2
1
...

Error:
1 1 100 0

Test 26

Group: 1, 2, 3

Verdict: ACCEPTED

input
2
1 2

correct output
(empty)

user output
2
? 1
1
? 2
2
...

Error:
1 1 100 0

Test 27

Group: 1, 2, 3

Verdict: ACCEPTED

input
2
2 1

correct output
(empty)

user output
2
? 1
2
? 2
1
...

Error:
1 1 100 0

Test 28

Group: 1, 2, 3

Verdict: ACCEPTED

input
3
1 1 1

correct output
(empty)

user output
3
? 2
1
? 3
1
...

Error:
1 1 100 0

Test 29

Group: 1, 2, 3

Verdict: ACCEPTED

input
3
1 1 2

correct output
(empty)

user output
3
? 2
1
? 3
2
...

Error:
1 1 100 0

Test 30

Group: 1, 2, 3

Verdict: ACCEPTED

input
3
1 2 1

correct output
(empty)

user output
3
? 2
2
? 3
1
...

Error:
1 1 100 0

Test 31

Group: 1, 2, 3

Verdict: ACCEPTED

input
3
2 1 1

correct output
(empty)

user output
3
? 2
1
? 3
1
...

Error:
1 1 100 0