CSES - Datatähti 2021 loppu - Results
 Task: Järjestäminen Sender: AtskaFin Submission time: 2021-01-23 18:42:48 +0200 Language: C++17 Status: READY Result: 0
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groupverdictscore
#10
#20
Test results
testverdicttimegroup
#10.01 s1, 2details
#20.01 s2details
#30.01 s1, 2details
#40.01 s1, 2details

### Compiler report

input/code.cpp: In function 'void sort()':
input/code.cpp:18:9: warning: 'index' may be used uninitialized in this function [-Wmaybe-uninitialized]
int index;
^~~~~

### Code

#include <iostream>
#include <vector>

using namespace std;

vector<int> v;

int n;

void swap(int a, int b) {
int tmp = v[a];
v[a] = v[b];
v[b] = tmp;
}

void sort() {
for (int i = 1; i <= n-4; i++) {
int index;
for (int j = 0; j < n; j++) {
if (v[j] == i) {
index = j;
break;
}
}

if (index < n-1) {
// käännä niin että luku ensimmäinen parissa
swap(i-1, index);
swap(i, index+1);
} else {
// käännä niin että luku toinen parissa
// index-3, index-2, index-1, index, index+1

// 1 2 3 4
// 3 4 1 2
// uusi index = index - 2
swap(index, index - 2);
swap(index - 1, index - 3);

swap(i-1, index-2);
swap(i, index-1);
}
/*
6 7 8

*/
}

if (v[n-1] != n) {
swap(n-1, n-3);
swap(n-2, n-4);
}
}

int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);

int t; cin >> t;
for (int ddd = 0; ddd < t; ddd++) {
cin>>n;

v.clear();
v.resize(n);
for (int i = 0; i < n; i++) cin >> v[i];

if (n == 1) {
cout << "YES";
} else if (n == 2) {
if (v[0] == 1) {
cout << "YES";
} else {
cout << "NO";
}
} else if (n == 3) {
if (v[0] == 1 && v[1] == 2) {
cout << "YES";
} else {
cout << "NO";
}
} else if (n == 4) {
if ((v[0] == 1 && v[1] == 2 && v[2] == 3 && v[3] == 4)
|| (v[0] == 3 && v[1] == 4 && v[2] == 1 && v[3] == 2)) {
cout << "YES";
} else {
cout << "NO";
}
} else if (n == 5 || n == 6) {
sort();
bool sorted = true;
for (int i = 0; i < n; i++) {
if (v[i] != i+1) sorted = false;
}

if (sorted) {
cout << "YES";
} else {
cout << "NO";
}
} else {
cout << "YES";
}

cout << "\n";
}
}

### Test details

Group: 1, 2

Verdict:

input
153
1
1
2
1 2
...

correct output
YES
YES
NO
NO
NO
...

user output
YES
YES
NO
NO
NO
...
Truncated

#### Test 2

Group: 2

Verdict:

input
1000
59
35 29 32 50 11 15 9 21 19 45 2...

correct output
YES
NO
YES
NO
YES
...

user output
YES
YES
YES
YES
YES
...
Truncated

Group: 1, 2

Verdict:

input
720
6
1 6 4 5 2 3
6
6 3 2 1 5 4
...

correct output
YES
NO
NO
NO
YES
...

user output
NO
NO
NO
NO
YES
...
Truncated

Group: 1, 2

Verdict:

input
1000
8
7 4 2 8 6 3 5 1
8
3 8 2 7 5 4 6 1
...

correct output
NO
NO
YES
NO
YES
...

user output
YES
YES
YES
YES
YES
...
Truncated