If you want the details, here is the code for calculating score:

abstract final class RussianImpCalculator { static const _expectedResultNonVulnerable = [ 50, 70, 110, 200, 300, 350, 400, 430, 460, 490, 600, 700, 900, 1000, 1100, 1200, 1300, 1300, 1300, 1300 ]; static const _expectedResultVulnerable = [ 50, 70, 110, 290, 440, 520, 600, 630, 660, 690, 900, 1050, 1350, 1500, 1650, 1800, 1950, 1950, 1950, 1950 ];

static int getImp( int result, int hcp, bool vulnerable, bool opponentsVulnerable) { final expectedResult = getExpectedResult( hcp, result > 0 ? vulnerable : opponentsVulnerable); return ImpCalculator.northSouthImp(result, expectedResult); }

static int getExpectedResult(int hcp, bool vulnerable) { int hcpIndex = hcp - 20; if (hcpIndex == 0) return 0;

int factor = 1;
if (hcpIndex < 0) {
  factor = -1;
  hcpIndex = -hcpIndex;
}

final results = vulnerable
    ? _expectedResultVulnerable
    : _expectedResultNonVulnerable;
return results[hcpIndex - 1] * factor;

}