oj.uz

Submission #468818

# Submission time Handle Problem Language Result Execution time Memory
468818 2021-08-29T18:36:23 Z errorgorn Cat (info1cup19_cat) C++17
55 / 100
 621 ms 43276 KB 
//雪花飄飄北風嘯嘯
//天地一片蒼茫

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << ": " << x << endl

#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define ub upper_bound

#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

const int MOD=998244353;

ll qexp(ll b,ll p,int m){
    ll res=1;
    while (p){
        if (p&1) res=(res*b)%m;
        b=(b*b)%m;
        p>>=1;
    }
    return res;
}

ll inv(ll i){
	return qexp(i,MOD-2,MOD);
}

ll fix(ll i){
	i%=MOD;
	if (i<0) i+=MOD;
	return i;
}

ll fac[1000005];
ll ifac[1000005];

ll nCk(int i,int j){
	if (i<j) return 0;
	return fac[i]*ifac[j]%MOD*ifac[i-j]%MOD;
}

int n;
int arr[200005];
int par[200005];
bool vis[200005];

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	
	fac[0]=1;
	rep(x,1,1000005) fac[x]=fac[x-1]*x%MOD;
	ifac[1000004]=inv(fac[1000004]);
	rep(x,1000005,1) ifac[x-1]=ifac[x]*x%MOD;
	
	int TC;
	cin>>TC;
	while (TC--){
		cin>>n;
		rep(x,0,n) cin>>arr[x];
		rep(x,0,n) par[x]=0;
		
		bool can=true;
		rep(x,0,n) if (arr[x]+arr[n-1-x]!=n+1) can=false;
		
		if (!can){
			cout<<"-1"<<endl;
			continue;
		}
		
		n/=2;
		rep(x,0,n) if (arr[x]>n) arr[x]=2*n+1-arr[x],par[x]=1;
		
		rep(x,0,n) arr[x]--;
		//rep(x,0,n) cout<<arr[x]<<" "; cout<<endl;
		//rep(x,0,n) cout<<par[x]<<" "; cout<<endl;
		
		vector<int> bad;
		rep(x,0,n) vis[x]=false;
		rep(x,0,n) if (!vis[x]){
			int curr=x;
			int npar=0;
			int pos=-1;
			
			do{
				vis[curr]=true;
				if (par[curr]) npar^=1,pos=curr;
				curr=arr[curr];
			} while (curr!=x);
			
			if (npar) bad.pub(pos);
		}
		
		if (sz(bad)%2==1){
			cout<<"-1"<<endl;
			continue;
		}
		
		//for (auto &it:bad) cout<<it<<" "; cout<<endl;
	
		vector<ii> v;
		rep(x,0,sz(bad)/2){
			v.pub(ii(bad[x*2]+1,2*n-bad[x*2+1]));
			swap(arr[bad[x*2]],arr[bad[x*2+1]]);
			par[bad[x*2]]=0,par[bad[x*2+1]]=0;
		}
		
		//rep(x,0,n) cout<<arr[x]<<" "; cout<<endl;
		//rep(x,0,n) cout<<par[x]<<" "; cout<<endl;
		
		rep(x,0,n) vis[x]=false;
		rep(x,0,n) if (!vis[x]){
			int curr=x;
			int npar=0;
			int pos=-1;
			
			do{
				vis[curr]=true;
				if (x!=curr){
					if (par[curr]) v.pub(ii(x+1,2*n-curr));
					else v.pub(ii(x+1,curr+1));				
				}
				curr=arr[curr];
			} while (curr!=x);
			
			if (npar) bad.pub(pos);
		}
		
		cout<<sz(v)<<" "<<sz(v)<<endl;
		for (auto &it:v) cout<<it.fi<<" "<<it.se<<endl;
	}
}

Subtask #1
6.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 16104 KB Correct number of moves

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 16124 KB Output is correct
2 Correct 40 ms 16140 KB Output is correct

Subtask #3
10.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 16104 KB Correct number of moves
2 Correct 40 ms 16124 KB Output is correct
3 Correct 40 ms 16140 KB Output is correct
4 Correct 43 ms 16632 KB Correct number of moves
5 Correct 27 ms 16256 KB Correct number of moves
6 Correct 26 ms 16204 KB Correct number of moves

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 16124 KB Output is correct
2 Correct 40 ms 16140 KB Output is correct
3 Correct 538 ms 25712 KB Output is correct
4 Correct 521 ms 25132 KB Output is correct
5 Correct 557 ms 27532 KB Output is correct

Subtask #5
14.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 16104 KB Correct number of moves
2 Correct 40 ms 16124 KB Output is correct
3 Correct 40 ms 16140 KB Output is correct
4 Correct 43 ms 16632 KB Correct number of moves
5 Correct 27 ms 16256 KB Correct number of moves
6 Correct 26 ms 16204 KB Correct number of moves
7 Correct 538 ms 25712 KB Output is correct
8 Correct 521 ms 25132 KB Output is correct
9 Correct 557 ms 27532 KB Output is correct
10 Correct 559 ms 39012 KB Correct number of moves
11 Correct 510 ms 37484 KB Correct number of moves
12 Correct 545 ms 43276 KB Correct number of moves
13 Correct 621 ms 42224 KB Correct number of moves
14 Correct 547 ms 40996 KB Correct number of moves