// Copyright 2010-2018 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

namespace Google.OrTools {

  using System;
  using System.Collections.Generic;

  public static class NestedArrayHelper {
    public static T[] GetFlatArray<T>(T[][] arr) {
      int flatLength = 0;
      for (var i = 0; i < arr.GetLength(0); i++)
        flatLength += arr [i]
                          .GetLength(0);

      int idx = 0;
      T[] flat = new T[flatLength];

      for (int i = 0; i < arr.GetLength(0); i++) {
        for (int j = 0; j < arr [i]
                                .GetLength(0);
             j++)
          flat[idx++] = arr [i]
          [j];
      }

      return flat;
    }

    public static T[] GetFlatArrayFromMatrix<T>(T[, ] arr) {
      int flatLength = arr.GetLength(0) * arr.GetLength(1);

      int idx = 0;
      T[] flat = new T[flatLength];

      for (int i = 0; i < arr.GetLength(0); i++) {
        for (int j = 0; j < arr.GetLength(1); j++) flat[idx++] = arr[i, j];
      }

      return flat;
    }

    public static int[] GetArraySecondSize<T>(T[][] arr) {
      var result = new int[arr.GetLength(0)];
      for (var i = 0; i < arr.GetLength(0); i++) {
        if (arr[i] != null) result[i] = arr[i].Length;
      }
      return result;
    }
  }
}  // namespace Google.OrTools