P'tit Library for KDS Code Challenge (October)

main.dart

// Copyright 2019 Alvyn Fasuyi. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file.import 'dart:math';

import 'dart:math';

main() async {
  final startFileReadTime = DateTime.now();
  // final input = [-2, -1, 0];
  // final input = [1, 2, 3, -2, 5];
  // final input = [-1, -2, -3, -4];
  // final input = [3, 5, -8, 2, 1];
  // final input = [3, 4, -3, 1, -8, 2, 1];

  const min = -10000, max = 10000;
  final input =
      await List.generate(1000000, (i) => min + Random().nextInt(max - min));

  final endFileReadTime = DateTime.now().difference(startFileReadTime);
  print(
    'Reading the ${input.length}x values input took @: ${endFileReadTime.inMilliseconds} milliSeconds',
  );

  await SentimentCalculator(
    sentiments: input,
    minValue: min,
  ).getBestSentiment();
}

// Copyright 2019 Alvyn Fasuyi. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file.

class SentimentCalculator {
  List<int> _sentiments;
  int _minValue;

  SentimentCalculator._internal(this._sentiments, this._minValue);
  factory SentimentCalculator({List<int> sentiments, int minValue}) =>
      SentimentCalculator._internal(
        sentiments,
        minValue,
      );

  Future getBestSentiment() async {
    final startTime = DateTime.now();
    final result = await _getSentiment(_sentiments);
    final elapsedTime = DateTime.now().difference(startTime).inMilliseconds;
    print('\nActual Calculation took @: $elapsedTime milliSeconds');
    print('Output: $result');
  }

  /* Future<double> _getBestSentiment(List<double> sentiments) async {
    if (sentiments == null) return null;
    if (sentiments.isEmpty) return Future.value(0);
    if (sentiments.length == 1) return Future.value(sentiments[0]);
    return await _getSentiment(sentiments);
  } */

  Future _getSentiment(List<int> sentiments) {
    final size = sentiments.length;
    var bestMax = _minValue;
    var currMax = 0;

    for (int i = 0; i < size; i++) {
      currMax = currMax + sentiments[i.toInt()];
      if (bestMax < currMax) bestMax = currMax;
      if (currMax < 0) currMax = 0;
    }
    return Future.value(bestMax);
  }
}