Submission #1754046

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Source Code Expand

#include <bits/stdc++.h>
#define long long long
#define up(i,a,b) for (int i=a; i<=b; i++)
#define down(i,a,b) for (int i=a; i>=b; i--)
#define endl '\n'
#define X first
#define Y second
#define II pair<int, int>
#define III pair<int, pair<int, int> >
#define debug(X) cerr<< #X << " = " <<X << endl
#define debug2(X,Y) cerr<< #X << " = " <<X << ","<<#Y<<" = "<<Y<<endl
#define show(X,a,b) {cerr << #X << " = "; up(__,a,b) cerr << X[__] << ' '; cerr << endl;}
#define gc getchar
#define pc putchar
using namespace std;
int n,x,a[200010],ok[200010];
void input()
{
    cin>>n>>x;
}

void solve()
{
	if (x==1 or x== 2*n-1)
	{
		cout<<"No"; return;
	}

    a[n]= x; a[n-1]= x-1; a[n+1]= x+1;
    if (n>2)
	{
		if (x!= 2) a[n-2]= x-2;
		else a[n-2]= x+2;
	}

    up(i,n-2,n+1) ok[a[i]]= 1;
    int cur= 1;
    up(i,1,2*n-1)
     if (!a[i])
	 {
	 	while (ok[cur]) cur++;
	 	a[i]= cur; ok[cur]= 1;
	 }
	 cout<<"Yes"<<endl;
	 up(i,1,2*n-1) cout<<a[i]<<endl;

}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);// don't use when interactive

    #ifdef I_Love_Pork
    #define TASK "tmp"
    freopen(TASK".inp","r",stdin);
    freopen(TASK".out","w",stdout);
	  #endif

    input();
    solve();

    return 0;
}

Submission Info

Judge Result