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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     ios::sync_with_stdio(false);
  6.     cin.tie(nullptr);
  7.  
  8.     int t;
  9.     cin >> t;
  10.     while (t--) {
  11.         int n;
  12.         cin >> n;
  13.         int N = 1 << n;
  14.  
  15.         vector<int> a(N);
  16.         iota(a.begin(), a.end(), 0);
  17.  
  18.         sort(a.begin(), a.end(), [&](int x, int y) {
  19.             int px = __builtin_popcount(x);
  20.             int py = __builtin_popcount(y);
  21.             if (px != py) return px > py;
  22.             return x < y;
  23.         });
  24.  
  25.         for (int i = 0; i < N; i++) {
  26.             cout << a[i] << (i + 1 < N ? ' ' : '\n');
  27.         }
  28.     }
  29.     return 0;
  30. }
  31.  
Success #stdin #stdout 0.01s 5292KB
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https://ideone.com/pESiHW
language:
C++ (gcc 8.3)
created:
18 days ago
visibility:
public

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