CSES - Datatähti Open 2021

CSES - Datatähti Open 2021 - Results

Submission details
Task:	Sorting
Sender:	YouKnowWho
Submission time:	2021-01-30 16:59:36 +0200
Language:	C++ (C++17)
Status:	READY
Result:	100

Feedback
group	verdict	score
#1	ACCEPTED	36
#2	ACCEPTED	64

Test results
test	verdict	time	group
#1	ACCEPTED	0.01 s	1, 2	details
#2	ACCEPTED	0.01 s	2	details
#3	ACCEPTED	0.01 s	1, 2	details
#4	ACCEPTED	0.01 s	1, 2	details

Code

#include<bits/stdc++.h>
using namespace std;
 
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t; cin >> t;
  while (t--) {
    int n; cin >> n;
    vector<int> a(n), b(n);
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      b[i] = i + 1;
    }
    int ok = 0;
    if (n <= 3) {
      ok = a == b;
    }
    else if (n == 4) {
      if (a == b || (a == vector<int>({3, 4, 1, 2}))) {
        ok = 1;
      }
    }
    else {
      int inv = 0;
      for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
          inv += a[i] > a[j];
        }
      }
      ok = inv % 2 == 0;
    }
    if (ok) {
      cout << "YES\n";
    }
    else {
      cout << "NO\n";
    }
  }
  return 0;
}

Test details

Test 1

Group: 1, 2

Verdict: ACCEPTED

input
`153 1 1 2 1 2 ...` view save

correct output
`YES YES NO NO NO ...` view save

user output
`YES YES NO NO NO ...` Truncated

Test 2

Group: 2

Verdict: ACCEPTED

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

correct output
`YES NO YES NO YES ...` view save

user output
`YES NO YES NO YES ...` Truncated

Test 3

Group: 1, 2

Verdict: ACCEPTED

input
`720 6 1 6 4 5 2 3 6 6 3 2 1 5 4 ...` view save

correct output
`YES NO NO NO YES ...` view save

user output
`YES NO NO NO YES ...` Truncated

Test 4

Group: 1, 2

Verdict: ACCEPTED

input
`1000 8 7 4 2 8 6 3 5 1 8 3 8 2 7 5 4 6 1 ...` view save

correct output
`NO NO YES NO YES ...` view save

user output
`NO NO YES NO YES ...` Truncated

Datatähti Open 2021

Sorting

Code

Test details

Test 1

Test 2

Test 3

Test 4

Tasks

Submissions (YouKnowWho)