Submission #861285

#	Time	Username	Problem	Language	Result	Execution time	Memory
861285		Ahmed57	Cat (info1cup19_cat)	C++17	10 / 100	310 ms	262144 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;i++){
            while(pos[i]!=i&&pos[n-i+1]!=n-i+1) {
                int tmp=pos[i];
                con.push_back({i,tmp});
                swap(pos[i],pos[tmp]);
                swap(pos[n-i+1],pos[n-tmp+1]);
            }
        }
        cout<<con.size()<<" "<<con.size()<<"\n";
        for(auto i:con)cout<<i.first<<" "<<i.second<<"\n";
    }
}

• Subtask 1: 0 / 15
• Subtask 2: 4 / 10
• Subtask 3: 0 / 25
• Subtask 4: 6 / 15
• Subtask 5: 0 / 35