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  1. #include <bits/stdc++.h>
  2. #define ll long long
  3.  
  4. using namespace std;
  5.  
  6. const int MOD = 1e9 + 7;
  7.  
  8. void solve()
  9. {
  10.     int n, d, l;
  11.     cin >> n >> d >> l;
  12.  
  13.     int rem = (n - 1) - l;
  14.     if(rem < 0){
  15.     	cout << -1 << "\n";
  16.     	return;
  17.  
  18.     }
  19.     if(rem + 2 == d){
  20.         int x = 2;
  21.         for(int i = 0; i < l; i++){
  22.             cout << 1 << " " << x << "\n";
  23.             x++;
  24.         }
  25.         while(x <= n){
  26.             cout << x - 1 << " " << x << "\n";
  27.             x++;
  28.         }
  29.     }else if(rem + 1 == d){
  30.         int x = 1;
  31.         for(int i = 0; i < d; i++){
  32.             cout << x << " " << x + 1 << "\n";
  33.             x++;
  34.         }
  35.         int p = x - 1;
  36.         x++;
  37.         for(int i = 0; i < l - 1; i++){
  38.             cout << p << " " << x << "\n";
  39.             x++;
  40.         }
  41.     }else{
  42.         cout  << -1 << "\n";
  43.     }
  44. }
  45.  
  46. int main()
  47. {
  48.     ios_base::sync_with_stdio(false);
  49.     cin.tie(NULL);
  50.  
  51.     //  cout << fixed << setprecision(7);
  52.     int t = 1;
  53.     cin >> t;
  54.     for (int i = 1; i <= t; i++)
  55.     {
  56.         // cout << "Case #" << i << ": ";
  57.         solve();
  58.     }
  59.     return 0;
  60. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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5
2 1 1
4 1 4
3 2 3
4 2 3
7 3 4
stdout
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1 2
-1
-1
1 2
1 3
1 4
1 2
2 3
3 4
3 5
3 6
3 7
https://ideone.com/GOmEO5
language:
C++14 (gcc 8.3)
created:
5 days ago
visibility:
public

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