CF1978C-rk1300-1.5h

一道构造题，我的做法似乎思维复杂度上远高于答案的做法，因而不是什么好做法，但幸好我最后还是调出来了，另外就是会爆ll...下意识写int的我根本想不起来用ll啊，看来不得不define int long long了

Code

#include <iostream>
#include <cstring>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#define int long long
using namespace std;

int n,m,k,fk;

void change(int rest_k,int pos)
{
	if(pos>n/2&&rest_k>0)
	{
		cout<<"NO"<<endl;
		return;
	}
	if(rest_k-(n-pos-(pos-1))>0)change(rest_k-(n-pos-(pos-1)),pos+1);
	else
	{
		//int p=1,ans=0;
		cout<<"YES"<<endl;
		if(rest_k>=1)
		{
			rest_k+=pos-1;
			for(int i=pos+1;i<=pos+1+rest_k-1;i++)
				cout<<i<<' ';//,ans+=abs(i-p),p++;
			cout<<pos<<' ';//,ans+=abs(pos-p),p++;
			for(int i=pos+1+rest_k;i<=n;i++)
				cout<<i<<' ';//,ans+=abs(i-p),p++;
		}
		else
		{
			for(int i=pos;i<=n;i++)
				cout<<i<<' ';//,ans+=abs(i-p),p++;
		}
		for(int i=pos-1;i>=1;i--)
			cout<<i<<' ';//,ans+=abs(i-p),p++;
		cout<<endl;//cout<<ans<<endl;if(ans!=fk)cout<<"error"<<endl;
	}
}

void solution()
{
	cin>>n>>k;
	if(k%2==1)cout<<"NO"<<endl;
	else
	{
		fk=k;
		k/=2;
		change(k,1);
	}
}

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	int T;
	cin>>T;
	while(T--)
		solution();
	return 0;
}