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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#615582 | #8939. Permutation | m107239 | WA | 1ms | 3576kb | C++23 | 4.7kb | 2024-10-05 19:22:38 | 2024-10-05 19:22:38 |
Judging History
answer
#include <iostream>
#include <map>
using ll = long long;
using namespace std;
static map<pair<int, int>, int> cache;
static int query(int l, int r) { // use 0-based, right exclusive index internally, but 1-based, right inclusive index externally
if (r - l < 2) {
return -1;
}
auto it = cache.find({l, r});
if (it != cache.end()) {
return it->second;
}
cout << "? " << l + 1 << " " << r << endl;
int x;
cin >> x;
return cache[{l, r}] = x - 1;
}
int solve(int n) {
int l = 0, r = n;
while (true) {
if (l + 1 == r) {
return l;
}
if (l + 2 == r) {
return l + (l == query(l, r));
}
int m = (l + r) / 2, ml = (l + m) / 2, mr = (m + r) / 2;
int s0 = query(l, r);
if (s0 < ml) {
int s1 = query(l, m);
if (s1 == s0) {
if (l + 1 == m) {
return l;
}
if (l + 2 == m) {
return l + (l == query(l, m));
}
int s2 = query(l, ml);
if (s2 == s0) {
r = ml;
} else {
l = ml;
r = m;
}
} else {
if (m + 1 == r) {
return m;
}
if (m + 2 == r) {
return m + (m == query(m, r));
}
int s2 = query(l, mr);
if (s2 == s0) {
l = m;
r = mr;
} else {
l = mr;
}
}
} else if (s0 < m) {
int s1 = query(l, m);
if (s1 == s0) {
if (l + 1 == m) {
return l;
}
if (l + 2 == m) {
return l + (l == query(l, m));
}
int s2 = query(ml, mr);
if (s2 == s0) {
l = ml;
r = m;
} else {
r = ml;
}
} else {
if (m + 1 == r) {
return m;
}
if (m + 2 == r) {
return m + (m == query(m, r));
}
int s2 = query(ml, mr);
if (s2 == s0) {
l = m;
r = mr;
} else {
l = ml;
}
}
} else if (s0 < mr) {
int s1 = query(m, r);
if (s1 == s0) {
if (m + 1 == r) {
return m;
}
if (m + 2 == r) {
return m + (m == query(m, r));
}
int s2 = query(ml, mr);
if (s2 == s0) {
l = m;
r = mr;
} else {
l = mr;
}
} else {
if (l + 1 == m) {
return l;
}
if (l + 2 == m) {
return l + (l == query(l, r));
}
int s2 = query(ml, mr);
if (s2 == s0) {
l = ml;
r = m;
} else {
r = ml;
}
}
} else {
int s1 = query(m, r);
if (s1 == s0) {
if (m + 1 == r) {
return m;
}
if (m + 2 == r) {
return m + (m == query(m, r));
}
int s2 = query(mr, r);
if (s2 == s0) {
l = mr;
} else {
l = m;
r = mr;
}
} else {
if (l + 1 == m) {
return l;
}
if (l + 2 == m) {
return l + (l == query(l, m));
}
int s2 = query(ml, r);
if (s2 == s0) {
l = ml;
r = m;
} else {
r = ml;
}
}
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
int ans = solve(n) + 1;
cout << "! " << ans << endl;
}
return 0;
}
// [9, 2, 7, 6, 3, 1, 8, 10, 5, 11, 4]
Details
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Test #1:
score: 0
Wrong Answer
time: 1ms
memory: 3576kb
input:
3 5 3 3 2 5 6 6 5 6
output:
? 1 5 ? 3 5 ? 2 3 ? 4 5 ! 4 ? 1 6 ? 4 6 ? 2 6 ! 3
result:
wrong answer Wrong prediction (test case 2)