Submission #755641

#	Time	Username	Problem	Language	Result	Execution time	Memory
755641		DJeniUp	Cat (info1cup19_cat)	C++17	100 / 100	933 ms	31288 KiB

cat

#include "bits/stdc++.h"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll>pairll;
typedef pair<ll,ull>pairull;
typedef pair<ll,pairll>pair3l;
typedef long double ld;
typedef pair<ld,ll>pairld;
 
#define fr first
#define sc second
#define pb push_back
#define endl '\n'
#define N 100007
//#define MOD 998244353
#define INF 10000000000007
#define eps 0.0000000001
 
ll t,n,d[2*N];

queue<pairll>res,g;

vector<ll>v;

int main(){
    
    cin>>t;
    while(t--){
        cin>>n;
        while(res.size()>0)res.pop();
        while(g.size()>0)g.pop();
        v.clear();
        for(int i=1;i<=n;i++){
            cin>>d[i];
        }
        ll fl=0;
        for(int i=1;i<=n/2;i++){
            if(d[i]+d[n-i+1]!=n+1)fl=-1;
            v.pb(i);
        }
        if(fl==-1){
            cout<<-1<<endl;
            continue;
        }
        for(int j=0;j<v.size();j++){
            ll i=v[j];
            //cout<<"! "<<i<<" "<<d[i]<<endl;
            if(i!=d[i]){
                if(d[n-i+1]==i){
                    g.push({i,d[i]});
                }else{
                    res.push({d[i],i});
                    ll x=d[i];
                    ll y=i;
                    swap(d[y],d[x]);
                    swap(d[n-y+1],d[n-x+1]);
                    v.pb(min(i,n-i+1));
                }
            }
        }
        if(g.size()%2==1){
            cout<<-1<<endl;
            continue;
        }
        while(g.size()>0){
            ll m1=g.front().fr;
            ll x=g.front().sc;
            g.pop();
            ll y=g.front().fr;
            g.pop();
            res.push({m1,y});
            res.push({y,x});
        }
        cout<<res.size()<<" "<<res.size()<<endl;
        while(res.size()>0){
            cout<<res.front().fr<<" "<<res.front().sc<<endl;
            res.pop();
        }
    }
 
    return 0;
}

Compilation message (stderr)

cat.cpp: In function 'int main()':
cat.cpp:50:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |         for(int j=0;j<v.size();j++){
      |                     ~^~~~~~~~~

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