CSES - Putka Open 2020 – 3/5 - Results
Submission details
Task:Vaihdot
Sender:Mahtimursu
Submission time:2020-10-16 18:53:06 +0300
Language:C++ (C++11)
Status:READY
Result:0
Feedback
groupverdictscore
#10
#20
Test results
testverdicttimegroup
#10.01 s1, 2details
#20.01 s2details

Code

#include <bits/stdc++.h>
typedef long long ll;
#define M 1000000007
using namespace std;
void test_case() {
int n;
cin >> n;
vector<int> v(n);
for (int i = 0; i < n; ++i) {
cin >> v[i];
}
vector<pair<int, int>> res;
for (int i = 0; i < n; ++i) {
if (v[i] == i + 1) continue; // oikea
int id = v[i];
if (abs(id - i - 1) == 1) continue;
int tg = v[v[i]-1];
v[v[i]-1] = v[i];
v[i] = tg;
res.push_back({i+1, id});
}
if (!is_sorted(v.begin(), v.end())) {
if (n < 4) {
cout << -1 << "\n";
return;
}
for (int i = 0; i < n; ++i) {
if (v[i] == i + 1) continue;
// Use first
if (i >= n - 2) {
res.push_back({i+1, 1});
res.push_back({i+2, 1});
res.push_back({i+1, 1});
v[i] = i + 1;
v[i + 1] = i + 2;
} else { // use last
res.push_back({i+1, n});
res.push_back({i+2, n});
res.push_back({i+1, n});
v[i] = i + 1;
v[i + 1] = i + 2;
}
}
}
// VASTAUS
cout << res.size() << "\n";
for (auto val : res) {
cout << val.first << " " << val.second << "\n";
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int t;
cin >> t;
for (int i = 0; i < t; ++i) {
test_case();
//cout << "\n";
}
return 0;
}

Test details

Test 1

Group: 1, 2

Verdict:

input
1000
1
1
2
1 2
...

correct output
0
0
-1
0
-1
...

user output
(empty)

Error:
munmap_chunk(): invalid pointer

Test 2

Group: 2

Verdict:

input
1000
79
49 42 77 41 37 61 46 55 7 72 4...

correct output
81
67 79
70 78
3 77
60 76
...

user output
(empty)

Error:
code: malloc.c:2401: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0)...