Submission #515679

#	Time	Username	Problem	Language	Result	Execution time	Memory
515679		Theo830	Cat (info1cup19_cat)	C++17	40 / 100	736 ms	4776 KiB

cat

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ii,ll>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
int main(void){
    ll t;
    cin>>t;
    while(t--){
        ll n;
        cin>>n;
        ll arr[n];
        vll a[2];
        ll posa = 0;
        bool b[n+5] = {0};
        f(i,0,n){
            cin>>arr[i];
            if(i < n/2 && arr[i] > n/2){
                posa++;
                b[i+1] = true;
            }
            arr[i] = min(arr[i],n + 1 - arr[i]);
            a[i >= n/2].pb(arr[i]);
        }
        reverse(all(a[1]));
        ll res = n / 2;
        bool v[n+5] = {0};
        f(i,0,n/2){
            if(!v[i+1]){
                res--;
                ll posoi = 0;
                ll pos = i+1;
                while(!v[pos]){
                    v[pos] = true;
                    posoi += b[pos];
                    pos = arr[pos - 1];
                }
                if(posoi % 2 == 1){
                    res++;
                }
            }
        }
        if(a[0] == a[1] && (posa % 2 == 0)){
            cout<<res<<" ";
            cout<<"0\n";
        }
        else{
            cout<<"-1\n";
        }
    }
}

• Subtask 1: 6 / 15
• Subtask 2: 4 / 10
• Subtask 3: 10 / 25
• Subtask 4: 6 / 15
• Subtask 5: 14 / 35