CSES - Datatähti Open 2021

CSES - Datatähti Open 2021 - Results

Submission details
Task:	Sorting
Sender:	Bench0310
Submission time:	2021-01-31 16:17:23 +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;
typedef long long ll;
 
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--)
    {
        int n;
        cin >> n;
        vector<int> a(n+1,0);
        for(int i=1;i<=n;i++) cin >> a[i];
        bool res=0;
        if(n<=3)
        {
            bool ok=1;
            for(int i=1;i<=n;i++) ok&=(a[i]==i);
            res=ok;
        }
        else if(n==4) res=(a==vector<int>{0,1,2,3,4}||a==vector<int>{0,3,4,1,2});
        else
        {
            int inv=0;
            for(int i=1;i<=n;i++) for(int j=i+1;j<=n;j++) inv+=(a[i]>a[j]);
            res=((inv%2)==0);
        }
        if(res) cout << "YES\n";
        else cout << "NO\n";
    }
//    for(int n=1;n<=10;n++)
//    {
//        set<vector<int>> s;
//        vector<int> v(n);
//        for(int i=0;i<n;i++) v[i]=i+1;
//        s.insert(v);
//        queue<vector<int>> q;
//        q.push(v);
//        while(!q.empty())
//        {
//            vector<int> a=q.front();
//            q.pop();
//            for(int i=0;i+1<n;i++)
//            {
//                for(int j=i+2;j+1<n;j++)
//                {
//                    swap(a[i],a[j]);
//                    swap(a[i+1],a[j+1]);
//                    if(s.find(a)==s.end())
//                    {
//                        q.push(a);
//                        s.insert(a);
//                    }
//                    swap(a[i],a[j]);
//                    swap(a[i+1],a[j+1]);
//                }
//            }
//        }
//        for(vector<int> a:s)
//        {
//            int inv=0;
//            for(int i=0;i<n;i++) for(int j=i+1;j<n;j++) inv+=(a[i]>a[j]);
//            assert((inv%2)==0);
//        }
//        int req=1;
//        for(int i=1;i<=n;i++) req*=i;
//        cout << "[" << n << ": " << s.size() << "/" << req << "]" << endl;
//    }
    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 (Bench0310)