How Can I Generate All Possible Permutations of a String or Integer Using Recursion?

List the arranging of the string/integer

Determine all the possible arrangements for the string or integer may be common programming interview questions. This article aims to intuitively explain and realize the arrangement process.

The principle behind the arrangement

arrangement involves different order arrangement elements, and the solution of the problem revolves around recursive

. Consider the following principles:

The arrangement of a single element is itself.

The arrangement of a group of elements includes connecting each element with the arrangement of the other elements.

For example, for the collection {a, b}, arranged as:

ab (a perm (b))

ba (b perm (a))

Recursive

Follow these principles, we can design a recursive function to generate arrangement:

code implementation

The following is a code example in C# and Python:

<code>makePermutations(permutation) {
  if (length permutation == 1) {
    return permutation;
  } else {
    var permutations = [];
    for (var i = 0; i < permutation.length; i++) {
      var first = permutation[i];
      var rest = permutation.substring(0, i) + permutation.substring(i + 1);
      var subPermutations = makePermutations(rest);
      for (var j = 0; j < subPermutations.length; j++) {
        permutations.push(first + subPermutations[j]);
      }
    }
    return permutations;
  }
}</code>

C#

python

By understanding the principle of arrangement and realizing recursive algorithms, you can effectively generate all possible arrangements of the string or integer.

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