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  1. //
  2. //  main.cpp
  3. //  Bitmask
  4. //
  5. //  Created by Himanshu on 18/07/22.
  6. //
  7.  
  8. #include<iostream>
  9. #include<cmath>
  10. #include <bitset>
  11. #include<vector>
  12. #define N 3
  13. using namespace std;
  14.  
  15. void findSubsets (int k, int ki[]) {
  16.  
  17.     long subsetCount = (long int)pow(2,(double)N);
  18.  
  19.     for (long i=0; i<subsetCount; i++) {
  20.  
  21.         int pos = 0;  //variable for current bit position (0th - N-1th)
  22.  
  23.         long x = i; //integer to be used for bitmasking (0 <= x < 2^N)
  24.  
  25.         bool flag = false;
  26.  
  27.         bitset<N> subset;
  28.  
  29.         while (x > 0) {
  30.  
  31.             //Checking if the last bit from the right is set or not
  32.             if (x&1) {
  33.  
  34.                 //Checking if the current bit is the excluded (ki) bit or not
  35.                 for (int j=0; j<k; j++) {
  36.                     if (pos == ki[j]) {
  37.                         flag = true;
  38.                     }
  39.                 }
  40.  
  41.                 if (flag) {
  42.                     break;
  43.                 } else {
  44.                     //Adding current bit to the subset
  45.                     subset.set(pos, 1);
  46.                 }
  47.  
  48.             } else {
  49.                 //Setting the current bit as 0 if it's unset in x
  50.                 subset.set(pos, 0);
  51.             }
  52.  
  53.             //shifting 1 bit to right, to check the next bit
  54.             //and incresing position (pos) of the current bit by 1
  55.             x = x >> 1;
  56.             pos++;
  57.         }
  58.  
  59.         if (!flag) {
  60.             cout<<subset<<endl;
  61.         }
  62.     }
  63.  
  64. }
  65.  
  66. int main() {
  67.  
  68.     int k = 1;
  69.     int *ki = new int[k]();
  70.     ki[0] = 0;
  71.  
  72.     cout<<"Subsets with 0th bit unset:"<<endl;
  73.     findSubsets(k, ki);
  74.  
  75.     return 0;
  76. }
Success #stdin #stdout 0.01s 5396KB
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stdin
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Standard input is empty
stdout
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Subsets with 0th bit unset:
000
010
100
110
https://ideone.com/CPl0gW
language:
C++14 (gcc 8.3)
created:
2 years ago
visibility:
secret

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