Submission #471501

#	Time	Username	Problem	Language	Result	Execution time	Memory
471501		NhatMinh0208	Cat (info1cup19_cat)	C++14	100 / 100	563 ms	30328 KiB

cat

#ifndef CPL_TEMPLATE
#define CPL_TEMPLATE
/*
	Normie's Template v2.5
	Changes:
    Added warning against using pragmas on USACO.
*/
// Standard library in one include.
#include <bits/stdc++.h>
using namespace std;
 
// ordered_set library.
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set(el) tree<el,null_type,less<el>,rb_tree_tag,tree_order_statistics_node_update>
 
// AtCoder library. (Comment out these two lines if you're not submitting in AtCoder.) (Or if you want to use it in other judges, run expander.py first.)
//#include <atcoder/all>
//using namespace atcoder;

//Pragmas (Comment out these three lines if you're submitting in szkopul or USACO.)
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast,unroll-loops,tree-vectorize")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
 
//File I/O.
#define FILE_IN "cseq.inp"
#define FILE_OUT "cseq.out"
#define ofile freopen(FILE_IN,"r",stdin);freopen(FILE_OUT,"w",stdout)
 
//Fast I/O.
#define fio ios::sync_with_stdio(0);cin.tie(0)
#define nfio cin.tie(0)
#define endl "\n"
 
//Order checking.
#define ord(a,b,c) ((a>=b)and(b>=c))
 
//min/max redefines, so i dont have to resolve annoying compile errors.
#define min(a,b) (((a)<(b))?(a):(b))
#define max(a,b) (((a)>(b))?(a):(b))

// Fast min/max assigns to use with AVX.
// Requires g++ 9.2.0.
template<typename T>
__attribute__((always_inline)) void chkmin(T& a, const T& b) {
    a=(a<b)?a:b;
}

template<typename T>
__attribute__((always_inline)) void chkmax(T& a, const T& b) {
    a=(a>b)?a:b;
}
 
//Constants.
#define MOD (ll(998244353))
#define MAX 300001
#define mag 320
const long double PI=3.14159265358979;
 
//Pairs and 3-pairs.
#define p1 first
#define p2 second.first
#define p3 second.second
#define fi first
#define se second
#define pii(element_type) pair<element_type,element_type>
#define piii(element_type) pair<element_type,pii(element_type)>
 
//Quick power of 2.
#define pow2(x) (ll(1)<<x)
 
//Short for-loops.
#define ff(i,__,___) for(int i=__;i<=___;i++)
#define rr(i,__,___) for(int i=__;i>=___;i--)
 
//Typedefs.
#define bi BigInt
typedef long long ll;
typedef long double ld;
typedef short sh;

// Binpow and stuff
ll BOW(ll a, ll x, ll p)
{
	if (!x) return 1;
	ll res=BOW(a,x/2,p);
	res*=res;
	res%=p;
	if (x%2) res*=a;
	return res%p;
}
ll INV(ll a, ll p)
{
	return BOW(a,p-2,p);
}
//---------END-------//
#endif
vector<int> vec;
vector<pii(int)> seq;
int n,m,i,j,k,t,t1,u,v,a,b;
int arr[200001];
int brr[100001];
int crr[100001];
int used[100001];
int main()
{
	fio;
    cin>>t;
    for (t1=0;t1<t;t1++) {
        cin>>n;
        seq.clear();
        for (i=1;i<=n;i++) {
            cin>>arr[i];
        }
        for (i=1;i<=n/2;i++) if (arr[i]+arr[n+1-i] != n+1) {
            cout<<-1<<endl;
            break;
        }
        if (i<=n/2) {
            continue;
        }
        for (i=1;i<=n/2;i++) {
            if (arr[i]<=n/2) {
                crr[arr[i]]=0;
                brr[arr[i]]=i;
            } else {
                crr[n+1-arr[i]]=1;
                brr[n+1-arr[i]]=i;
            }
            used[i]=0;
        }
        for (i=1;i<=n/2;i++) if (!used[i]) {
            u=i;
            vec.clear();
            while(true) {
                used[u]=1;
                vec.push_back(u);
                u=brr[u];
                if (used[u]) break;
            }

            for (j=1;j<vec.size();j++) {
                u=vec[0];
                v=vec[j];
                if (crr[v]) {
                    crr[u]^=1;
                    crr[v]^=1;
                    seq.push_back({brr[u],n+1-brr[v]});
                } else {
                    seq.push_back({brr[u],brr[v]});
                }
                swap(brr[u],brr[v]);
            }
        }
        vec.clear();
        for (i=1;i<=n/2;i++) if (crr[i]) {
            vec.push_back(i);
        }
        if (vec.size()%2) {
            cout<<-1<<endl;
            continue;
        } else {
            for (i=0;i<vec.size();i+=2) {
                u=vec[i];
                v=vec[i+1];
                seq.push_back({brr[u],brr[v]});
                seq.push_back({brr[u],n+1-brr[v]});
            }
        }
        cout<<seq.size()<<' '<<seq.size()<<endl;
        for (auto g : seq) {
            cout<<g.fi<<' '<<g.se<<endl;
        }
    }
}
// Normie28;
/*
abcd
badc
dcba
cdab

*/

Compilation message (stderr)

cat.cpp:23: warning: ignoring '#pragma comment ' [-Wunknown-pragmas]
   23 | #pragma comment(linker, "/stack:200000000")
      | 
cat.cpp: In function 'int main()':
cat.cpp:144:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  144 |             for (j=1;j<vec.size();j++) {
      |                      ~^~~~~~~~~~~
cat.cpp:165:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  165 |             for (i=0;i<vec.size();i+=2) {
      |                      ~^~~~~~~~~~~

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