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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. long long n,k;
  4. string s;
  5. void backtrack(long long pos, long long cnt)
  6. {
  7.     if(pos==n+1)
  8.     {
  9.         for (long long i=1; i<s.size(); i++)
  10.         {
  11.             cout << s[i];
  12.         }
  13.         cout << "\n";
  14.         return;
  15.     }
  16.     if(pos==1)
  17.     {
  18.         for (long long i=0; i<=1; i++)
  19.         {
  20.             s[2*pos-1]=char(i+'0');
  21.             s[2*pos]=' ';
  22.             if(i==1)
  23.             {
  24.                 backtrack(pos+1,cnt+1);
  25.             }
  26.             else if(k-cnt<=(n-pos)/2+(n-pos)%2)
  27.             {
  28.                 backtrack(pos+1,cnt);
  29.             }
  30.         }
  31.         return;
  32.     }
  33.     else
  34.     {
  35.         for (long long i=(s[2*(pos-1)-1]=='0'&&(n-pos)/2+(n-pos)%2<max(0ll,k-cnt)); i<=(!(s[2*(pos-1)-1]=='1'&&(n-pos)/2<max(0ll,k-cnt))); i++)
  36.         {
  37.             s[2*pos-1]=char(i+'0');
  38.             s[2*pos]=' ';
  39.             if(i==0)
  40.             {
  41.                 backtrack(pos+1,cnt);
  42.             }
  43.             else if(i==1 && s[2*(pos-1)-1]=='0')
  44.             {
  45.                 backtrack(pos+1,cnt+1);
  46.             }
  47.             else
  48.             {
  49.                 backtrack(pos+1,cnt);
  50.             }
  51.         }
  52.     }
  53. }
  54. int main()
  55. {
  56.     ios_base::sync_with_stdio(0);
  57.     cin.tie(0);
  58.     cin >> n >> k;
  59.     for (long long i=1; i<=2*n; i++)
  60.     {
  61.         s+=' ';
  62.     }
  63.     backtrack(1,0);
  64. }
  65.  
Success #stdin #stdout 0s 5320KB
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language:

						
C++14 (gcc 8.3)

					

					

						
created:
								
						
4 days ago

					

					

						
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