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  • [Algorithm] Print All Subsets of a Set

    Let's say given a number of array, you should print out, all the subet of this array.

    Example: [1, 2]

    Output:

    > ""

    > 1
    > 2

    > 1,2

    The number of subset should be 2^n... 

    function print_set(subset) {
      if (subset.length === 0) {
        console.log('empty');
      }
      console.log(subset.filter(Boolean).join(','));
    }
    
    
    function all_subsets(given_array) {
    
      function helper(given_array, subset, i) {
        if (given_array.length === 0) {
          print_set([]);
        }
    
        if (i === given_array.length) {
          print_set(subset);
          return;
        }
    
        // in case of not include the current item
        subset[i] = null
        console.log(`set i: ${i} to null`);
        helper(given_array, subset, i + 1);
        // in case of inlcude the current item
        subset[i] = given_array[i]
        console.log(`set i: ${i} to ${given_array[i]}`);
        helper(given_array, subset, i + 1)
      }
      let subset = new Array(given_array.length);
      helper(given_array, subset, 0);
    }
    
    const data = [1, 2];
    all_subsets(data);
    /**
    set i: 0 to null
    set i: 1 to null
    ""
    set i: 1 to 2
    2
    set i: 0 to 1
    set i: 1 to null
    1
    set i: 1 to 2
    1
     */
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  • 原文地址:https://www.cnblogs.com/Answer1215/p/10507838.html
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