Submission #519119

#	Time	Username	Problem	Language	Result	Execution time	Memory
519119		lucri	Cat (info1cup19_cat)	C++17	40 / 100	902 ms	12588 KiB

cat

#include <iostream>
using namespace std;
int ans1[6000010],v[3000010],r,n,ans2[6000010],ans,poz[3000010];
int main()
{
    int t;
    cin>>t;
    ++t;
    while(--t)
    {
        int ver=0;
        cin>>n;
        for(int i=1;i<=n;++i)
        {
            cin>>v[i];
            poz[v[i]]=i;
        }
        n/=2;
        for(int i=1;i<=n;++i)
        {
            if(v[i]+v[2*n+1-i]!=2*n+1)
            {
                ver=1;
                break;
            }
            if(v[i]>n)
                ++ver;
        }
        if(ver%2==1)
        {
            cout<<-1<<'\n';
            continue;
        }
        ans=0;
        ver=0;
        for(int i=1;i<=n;++i)
        {
            if(v[i]>n)
            {
                if(poz[i]>n&&poz[i]+i!=2*n+1)
                {
                    ++ans;
                    ans1[ans]=poz[i];
                    ans2[ans]=i;
                    swap(v[i],v[poz[i]]);
                    swap(v[2*n+1-i],v[2*n+1-poz[i]]);
                    swap(poz[v[2*n+1-i]],poz[v[2*n+1-poz[i]]]);
                    swap(poz[v[i]],poz[poz[i]]);
                }
                else if(poz[i]<=n&&poz[poz[i]]>n&&i+poz[poz[i]]!=n*2+1)
                {
                    ++ans;
                    ans1[ans]=poz[i];
                    ans2[ans]=i;
                    swap(v[i],v[poz[poz[i]]]);
                    swap(v[2*n+1-i],v[2*n+1-poz[poz[i]]]);
                    swap(poz[v[2*n+1-i]],poz[v[2*n+1-poz[poz[i]]]]);
                    swap(poz[v[i]],poz[poz[poz[i]]]);
                }
            }
        }
        for(int i=1;i<=n;++i)
        {
            if(v[i]>n)
            {
                if(ver==0)
                    ver=i;
                else
                {
                    ++ans;
                    ans1[ans]=ver;
                    ans2[ans]=2*n-i+1;
                    swap(v[i],v[2*n-ver+1]);
                    swap(v[ver],v[2*n-i+1]);
                    swap(poz[v[i]],poz[v[2*n-ver+1]]);
                    swap(poz[v[ver]],poz[v[2*n-i+1]]);
                    ver=0;
                }
            }
        }
        for(int i=1;i<=n;++i)
        {
            while(v[i]!=i)
            {
                ++ans;
                ans1[ans]=v[i];
                ans2[ans]=i;
                swap(v[i],v[v[i]]);
            }
        }
        cout<<ans<<' '<<ans<<'\n';
        for(int i=1;i<=ans;++i)
            cout<<ans1[i]<<' '<<ans2[i]<<'\n';
    }
    return 0;
}

• Subtask 1: 6 / 15
• Subtask 2: 10 / 10
• Subtask 3: 3.75 / 25
• Subtask 4: 15 / 15
• Subtask 5: 5.25 / 35