day 63 part with permutatio // to get permutation with no same adjacent elements

main.dart

void addToList(List<dynamic> numbers, List<List<dynamic>> temp) {
  List<dynamic> tempo = [];
  numbers.forEach((integer) {
    tempo.add(integer);
  });
  temp.add(tempo);
}

void swap(List<dynamic> list, int i, int j) {
  dynamic temp = list[i];
  list[i] = list[j];
  list[j] = temp;
}

List<List<dynamic>> permute(List<dynamic> numbers, int start) {
  List<List<dynamic>> temp = [];
  if (start == numbers.length - 1) {
    addToList(numbers, temp);
    return temp;
  }
  for (int i = start; i < numbers.length; i++) {
    swap(numbers, start, i);
    temp.addAll(permute(numbers, start + 1));
    swap(numbers, start, i);
  }
  return temp;
}

int getPermutationWithoutSameAdjacentCharacters(String word) {
  List<String> wordList = word.split('').toList();
  List<List<dynamic>> output = permute(wordList, 0);
  int count = 0;
  output.forEach((word) {
    if (!isSameCharactersAdjacent(word)) {
      count++;
    }
  });
  return count++;
}

bool isSameCharactersAdjacent(List<dynamic> word) {
  for (int i = 0; i < word.length - 1; i++) {
    if (word[i] == word[i + 1]) {
      return true;
    }
  }
  return false;
}

void main() {

  print(getPermutationWithoutSameAdjacentCharacters("aabb"));
}