Submission #2545510

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define FOR(i,a,n) for (int i = a; i < (int)n; ++i)
#define REP(i,n) FOR(i,0,n)
#define whole(f,x,...) ([&](decltype((x)) whole) { \
    return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)
template<typename T> bool chmin(T &a, const T &b) {if (a > b) { a = b; return true; }return false;}
template<typename T> bool chmax(T &a, const T &b) {if (a < b) { a = b; return true; }return false;}

using ll = int_fast64_t;

constexpr ll INF = (1e9);
constexpr ll MOD = (1e9+7);

int main() {
  ll n, x; cin >> n >> x;
  vector<ll> ans(2*n-1);
  if (x == 1 || x == 2*n-1) {
    cout << "No" << endl;
    return 0;
  }
  if (n == 2) {
    cout << "Yes" << endl;
    cout << 1 << endl << 2 << endl << 3 << endl;
    return 0;
  }
  if (x == 2) {
    ans[n-2] = 3, ans[n-1] = 2, ans[n] = 1, ans[n+1] = 4;
    FOR(i,5,2*n) {
      if (i-1 <= n+1) ans[i-5] = i;
      else ans[i-1] = i;
    }
  } else {
    ans[n-2] = x-1, ans[n-1] = x, ans[n] = x+1, ans[n+1] = x-2;
    FOR(i,1,2*n) {
      if (x-2 <= i && i <= x+1) continue;
      if (i < x-2 && i-1 < n-2) ans[i-1] = i;
      else if (i < x-2) ans[i+3] = i;
      else if (i-1 <= n+1) ans[i-5] = i;
      else ans[i-1] = i;
    }
  }
  cout << "Yes" << endl;
  REP(i,ans.size()) cout << ans[i] << endl;
  return 0;
}

Submission Info

Judge Result