CSES - Datatähti Open 2021

CSES - Datatähti Open 2021 - Results

Submission details
Task:	Sorting
Sender:	koosaga
Submission time:	2021-01-30 11:24:36 +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	0.02 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;
const int MAXN = 105;
using lint = long long;
 
void solve(){
	int n; cin >> n;
	vector<int> a(n);
	for(auto &i : a) cin >> i;
	int ret = 0;
	for(int i=0; i<n; i++){
		for(int j=i+1; j<n; j++){
			if(a[j] < a[i]) ret++;
		}
	}
	if(n <= 3){
		puts(ret ? "NO" : "YES");
	}
	else if(n > 4){
		puts(ret % 2 ? "NO" : "YES");
	}
	else{
		if(is_sorted(a.begin(), a.end())) puts("YES");
		else{
			swap(a[0], a[2]);
			swap(a[1], a[3]);
			puts(is_sorted(a.begin(), a.end()) ? "YES" : "NO");
		}
	}
}
 
int main(){
	int t; cin >> t;
	while(t--) solve();
}

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 (koosaga)