Submission #861277

#	Time	Username	Problem	Language	Result	Execution time	Memory
861277		Ahmed57	Cat (info1cup19_cat)	C++17	16 / 100	1062 ms	8484 KiB

cat

#include <bits/stdc++.h>

using namespace std;
vector<pair<int,int>> con;
bool vis[200001];int arr[200001];
int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);
    int t;cin>>t;
    z:while(t--){
        int n;cin>>n;
        for(int i = 1;i<=n;i++)vis[i] = 0;
        con.clear();
        int pos[n+1];
        for(int i = 1;i<=n;i++){
            cin>>arr[i];pos[arr[i]] = i;
        }
        int g = 0;int lol = 0;
        for(int i = 1;i<=n/2;i++){
            if(arr[i]!=i)g++;
            if(n-arr[i]+1!=arr[n-i+1]){
                cout<<-1<<endl;
                goto z;
            }if(arr[i]>n/2){
                lol++;
            }
        }
        if(lol&1){
            cout<<-1<<endl;
            goto z;
        }
        for(int i = 1;i<=n/2;i++){
            if(!vis[i]){
                int st = i;
                vis[i] = 1;
                int e = arr[i];
                while(vis[e]==0){
                    vis[e] = 1;
                    con.push_back({e,i});
                    e = arr[e];
                }
            }
        }
        cout<<con.size()<<" "<<con.size()<<endl;
        for(auto i:con)cout<<i.first<<" "<<i.second<<endl;
    }
}

Compilation message (stderr)

cat.cpp: In function 'int main()':
cat.cpp:33:21: warning: unused variable 'st' [-Wunused-variable]
   33 |                 int st = i;
      |                     ^~
cat.cpp:13:13: warning: variable 'pos' set but not used [-Wunused-but-set-variable]
   13 |         int pos[n+1];
      |             ^~~

• Subtask 1: 2.25 / 15
• Subtask 2: 10 / 10
• Subtask 3: 3.75 / 25
• Subtask 4: 0 / 15
• Subtask 5: 0 / 35