Repo created

generator/cells_merger.hpp

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+#pragma once
+
+#include "geometry/point2d.hpp"
+#include "geometry/rect2d.hpp"
+
+#include <cstddef>
+#include <cstdint>
+#include <map>
+#include <optional>
+#include <utility>
+#include <vector>
+
+namespace generator
+{
+namespace cells_merger
+{
+struct CellWrapper
+{
+  static CellWrapper const kEmpty;
+
+  CellWrapper() = default;
+  CellWrapper(m2::RectD const & cell) : m_cell(cell) {}
+
+  m2::RectD const & GetCell() const { return m_cell; }
+  void SetTopLeft(size_t val) { m_topLeft = val; }
+  size_t GetTopLeft() const { return m_topLeft; }
+  void SetTopRight(size_t val) { m_topRight = val; }
+  size_t GetTopRight() const { return m_topRight; }
+  void SetBottomLeft(size_t val) { m_bottomLeft = val; }
+  size_t GetBottomLeft() const { return m_bottomLeft; }
+  void SetBottomRight(size_t val) { m_bottomRight = val; }
+  size_t GetBottomRight() const { return m_bottomRight; }
+  void CalcSum() { m_sum = m_topLeft + m_topRight + m_bottomLeft + m_bottomRight; }
+  size_t GetSum() const { return m_sum; }
+
+private:
+  m2::RectD m_cell;
+  size_t m_topLeft = 0;
+  size_t m_topRight = 0;
+  size_t m_bottomLeft = 0;
+  size_t m_bottomRight = 0;
+  size_t m_sum = 0;
+};
+
+// CellsMerger combines square cells to large square cells, if possible. This is necessary to reduce
+// the number of cells. For example, later they can be used to build the index.
+// Important: input cells are disjoint squares that have the same size.
+// The algorithm does not guarantee that the optimal solution will be found.
+class CellsMerger
+{
+public:
+  explicit CellsMerger(std::vector<m2::RectD> && cells);
+
+  std::vector<m2::RectD> Merge();
+
+private:
+  bool Has(int32_t x, int32_t y) const;
+  bool Has(m2::PointI const & xy) const;
+  CellWrapper & Get(m2::PointI const & xy);
+  CellWrapper & Get(int32_t x, int32_t y);
+  CellWrapper const & TryGet(int32_t x, int32_t y, CellWrapper const & defaultValue = CellWrapper::kEmpty) const;
+
+  void CalcSum();
+  std::optional<m2::PointI> FindMax() const;
+  std::optional<m2::PointI> FindDirection(m2::PointI const & startXy) const;
+  m2::PointI FindBigSquare(m2::PointI const & xy, m2::PointI const & direction) const;
+  m2::RectD Union(m2::PointI const & startXy);
+  void Remove(m2::PointI const & minXy, m2::PointI const & maxXy);
+
+  std::map<m2::PointI, CellWrapper> m_matrix;
+  int32_t m_maxX = 0;
+  int32_t m_maxY = 0;
+};
+
+std::vector<m2::RectD> MakeNet(double step, double minX, double minY, double maxX, double maxY);
+}  // namespace cells_merger
+}  // namespace generator