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ID	Problem	Submitter	Result	Time	Memory	Language	File size	Submit time	Judge time
#402434	#6394. Turn on the Light	iwew	WA	1ms	3708kb	C++20	1.5kb	2024-04-30 16:00:04	2024-04-30 16:00:41

Judging History

你现在查看的是最新测评结果

[2024-04-30 16:00:41]
评测

测评结果：WA
用时：1ms
内存：3708kb

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[2024-04-30 16:00:04]
提交

answer

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

typedef long long ll;

const int N = 1e6 + 10;

bool vis[N];

int ask(int x) {
    cout << "? " << x << endl;
    int t;
    cin >> t;
    return t;
}

void dfs(int L, int R, int &ans, int lstd) {
    int tmp = ask((L + R) >> 1);
    if(tmp == lstd) {
        ans = (L + R) >> 1;
        return;
    }

    auto take = [&](auto &&take, int l, int r, bool dir, int &nowd) -> void {
        int mid = (l + r) >> 1;
        auto curd = ask(mid);
        if(curd == nowd) {
            ans = mid;
            return;
        }
        if(l == r) {
            nowd = curd;
            return;
        }

        if(curd > nowd) {
            if(dir) take(take, l, mid - 1, dir, curd);
            else take(take, mid + 1, r, dir, curd);
        }
        else {
            if(curd == 0) {
                if(dir) dfs(mid + 1, r, ans, curd);
                else dfs(l, mid - 1, ans, curd);
            } else {
                if(dir) take(take, mid + 1, r, dir, curd);
                else take(take, l, mid - 1, dir, curd);
            }
        }
        nowd = curd;
    };

    take(take, L, ((L + R) >> 1) - 1, true, tmp);
    if(ans != -1) return;
    take(take, ((L + R) >> 1) + 1, R, false, tmp);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n;
    cin >> n;
    int ans = -1;
    dfs(1, n, ans, 0);
    cout << "! " << ans << '\n';
    return 0;
}

Source code, Language: C++20

Details

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Test #1:

score: 100

Accepted

time: 1ms

memory: 3700kb

input:

output:

? 2
? 1
? 3
! 3

result:

ok Correct position at 3

Test #2:

score: 0

Accepted

time: 1ms

memory: 3620kb

input:

output:

? 5
? 2
? 1
? 8
? 6
? 7
! 7

result:

ok Correct position at 7

Test #3:

score: 0

Accepted

time: 1ms

memory: 3584kb

input:

output:

? 5
? 2
? 1
? 7
? 8
? 9
! 9

result:

ok Correct position at 9

Test #4:

score: 0

Accepted

time: 1ms

memory: 3708kb

input:

output:

? 4
? 2
? 1
? 6
? 7
? 8
! 8

result:

ok Correct position at 8

Test #5:

score: 0

Accepted

time: 0ms

memory: 3704kb

input:

output:

? 4
? 2
? 1
? 6
? 5
! 5

result:

ok Correct position at 5

Test #6:

score: -100

Wrong Answer

time: 1ms

memory: 3652kb

input:

6
1
2

output:

? 3
? 1
? 0

result:

wrong answer Integer parameter [name=x] equals to 0, violates the range [1, 6]