CSES - Datatähti 2021 loppu - Results
 Task: Järjestäminen Sender: Epe Submission time: 2021-01-23 19:21:14 +0200 Language: C++11 Status: READY Result: 0
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Test results
testverdicttimegroup
#10.01 s1, 2details
#2--2details
#30.01 s1, 2details
#40.01 s1, 2details

### Code

```#include <bits/stdc++.h>
typedef long long ll;
using namespace std;

int arr[100001]; //arr
int pos[100001]; //i to p
int n;
int chk(){
for(int i = 1; i <= n; i++){
if(i != arr[i]){
return i-1;
}
}
return n;
}
bool swp(int a, int b){
if(a < 0) return 0;
swap(arr[a], arr[b]);
pos[arr[a]] = a;
pos[arr[b]] = b;

swap(arr[a+1], arr[b+1]);
pos[arr[a+1]] = a+1;
pos[arr[b+1]] = b+1;
return 1;
}
int main(){
int q;
cin >> q;
for(int i = 0; i < q; i++){
cin >> n;
for(int p = 1; p <= n; p++){
int t;
cin >> t;
arr[p] = t;
pos[t] = p;
}
int s = chk();

while(s < n){
int t = s+1;
if(pos[t] == t){
s++;
continue;
}
int apos = pos[t];
if(apos < n){
swp(apos, t);
} else {
if(apos-2 > s && apos-2 >= 0) {
swp(apos, apos - 2);
} else {
cout << "NO\n";
break;
}

}
}
if(s == n){
cout << "YES\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
YES
...
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
(empty)

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
NO
NO
NO
NO
NO
...
Truncated