AND Equation

main.dart

List<int> toCombine(List<int> A) {
  A.add(A[0]);
  A.removeRange(0, 1);

  return A;
}

class ANDEquation {
  int _counter = 0;

  int restoreY([List<int> A = null]) {
    int result;

    try {
      if (A.isNotEmpty) {
        Map<int, int> N = A.sublist(0, (A.length - 1)).asMap();
        int Nlen = N.length;
        int residue = A[A.length - 1];

        if (this._counter < A.length) {
          int i = 0;

          while (i < Nlen) {
            if (result == null) {
              result = N[i];
            } else {
              result &= N[i];
            }

            i++;
          }

          if (result != residue) {
            ++this._counter;
            return this.restoreY(toCombine(A));
          }
        } else {
          this._counter = 0;

          if (result != residue) {
            result = -1;
          }
        }
      }

      return result;
    } catch (e) {}

    return null;
  }
}

void main() {
  ANDEquation AEq = new ANDEquation();

  print(AEq.restoreY([1, 3, 5]));
  print(AEq.restoreY([31, 7]));
  print(AEq.restoreY([31, 7, 7]));
  print(AEq.restoreY([1,0,0,1,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,0,1,0,1,1,0,0,0,1]));
  print(AEq.restoreY([191411,256951,191411,191411,191411,256951,195507,191411,192435,191411,191411,195511,191419,191411,256947,191415,191475,195579,191415,191411,191483,191411,191419,191475,256947,191411,191411,191411,191419,256947, 191411,191411,191411]));
  print(AEq.restoreY([1362,1066,1659,2010,1912,1720,1851,1593,1799,1805,1139,1493,1141,1163,1211]));
  print(AEq.restoreY([2, 3, 7, 19]));
  print(AEq.restoreY());
  print(AEq.restoreY([]));
  print(AEq.restoreY([1372]));
  print(AEq.restoreY([-31, 7, 7]));
  print(AEq.restoreY([0, 0, 0]));
  print(AEq.restoreY([1, 2, 3]));
  print(AEq.restoreY([7, 31, 7]));
  print(AEq.restoreY([100, 31, 7]));
  print(AEq.restoreY([9, 1, 21]));
  print(AEq.restoreY([-9, -1, -21]));
}

TO TEST THE CODE, CLICK TO THE NEXT DartPad LINK

https://dartpad.dartlang.org/1e05c0f09490ed612946f97d4568eafd

• Running the code executes the main() function which runs some tests.
• Clicking 'Run' button to test the code.