mgrettondann/partridge-cpp
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[1/n]: Refactor x() & y() calls on position

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The goal of this sequence of patches is to end up representing a
position as a single integer index into the grid instead of an (x, y)
pair.  I believe this will have better performance.

First step move all calls of x(), y() into calls on methods of Results &
Grid as in the future these will need to use the length of the grid.
This commit is contained in:
Matthew Gretton-Dann
2025-09-04 10:53:20 +02:00
parent 65569982ee
commit e557933590
1 changed files with 37 additions and 42 deletions
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79
main.cc
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@@ -19,12 +19,6 @@ namespace {
/** (x, y) pair storing a position. */
using Pos = std::pair<size_t, size_t>;
/** Get x co-ordinate from position */
auto x(Pos const &p) noexcept -> size_t { return p.first; }
/** Get y co-ordinate from position */
auto y(Pos const &p) noexcept -> size_t { return p.second; }
/** A square - consisting of position of closest corner to origin, and side-length.
*/
struct Square {
@@ -46,10 +40,7 @@ namespace {
~Square() noexcept = default;
/** Get x co-ordinate of closest corner to origin. */
auto x() const noexcept -> size_t { return ::x(pos_); }
/** Get y co-ordinate of closest corner to origin. */
auto y() const noexcept -> size_t { return ::y(pos_); }
auto pos() const noexcept -> Pos { return pos_; }
/** Get side length. */
auto length() const noexcept -> size_t { return length_; }
@@ -75,8 +66,7 @@ namespace {
/** Output the grid. */
auto output() const -> void {
std::string out;
out.resize(length_ * length_);
std::string out(length_ * length_, '.');
for (auto const& sq : squares_) {
prettify_sq(out, sq);
}
@@ -93,34 +83,37 @@ namespace {
s[x + y * length_] = c;
}
static auto sq_x(Square const& sq) noexcept -> size_t { return sq.pos().first; }
static auto sq_y(Square const& sq) noexcept -> size_t { return sq.pos().second; }
auto prettify_sq(std::string& s, Square const &sq) const noexcept -> void {
switch (sq.length()) {
case 1: set(s, sq.x(), sq.y(), '*');
case 1: set(s, sq_x(sq), sq_y(sq), '*');
break;
case 2: set(s, sq.x(), sq.y(), '+');
set(s, sq.x() + 1, sq.y(), '+');
set(s, sq.x(), sq.y() + 1, '+');
set(s, sq.x() + 1, sq.y() + 1, '+');
case 2: set(s, sq_x(sq), sq_y(sq), '+');
set(s, sq_x(sq) + 1, sq_y(sq), '+');
set(s, sq_x(sq), sq_y(sq) + 1, '+');
set(s, sq_x(sq) + 1, sq_y(sq) + 1, '+');
break;
default: {
auto n = sq.length();
set(s, sq.x(), sq.y(), '+');
set(s, sq.x() + n - 1, sq.y(), '+');
set(s, sq.x(), sq.y() + n - 1, '+');
set(s, sq.x() + n - 1, sq.y() + n - 1, '+');
set(s, sq_x(sq), sq_y(sq), '+');
set(s, sq_x(sq) + n - 1, sq_y(sq), '+');
set(s, sq_x(sq), sq_y(sq) + n - 1, '+');
set(s, sq_x(sq) + n - 1, sq_y(sq) + n - 1, '+');
for (size_t i = 1; i < n - 1; ++i) {
set(s, sq.x() + i, sq.y(), '-');
set(s, sq.x() + i, sq.y() + n - 1, '-');
set(s, sq.x(), sq.y() + i, '|');
set(s, sq_x(sq) + i,sq_y(sq), '-');
set(s, sq_x(sq) + i, sq_y(sq) + n - 1, '-');
set(s, sq_x(sq), sq_y(sq) + i, '|');
for (size_t j = 1; j < n - 1; ++j) {
set(s, sq.x() + j, sq.y() + i, ' ');
set(s, sq_x(sq) + j, sq_y(sq) + i, ' ');
}
set(s, sq.x() + n - 1, sq.y() + i, '|');
set(s, sq_x(sq) + n - 1, sq_y(sq) + i, '|');
}
size_t i = sq.x() + n - 1;
size_t i = sq_x(sq) + n - 1;
while (n != 0) {
set(s, --i, sq.y() + 1, '0' + (n % 10));
set(s, --i, sq_y(sq) + 1, '0' + (n % 10));
n /= 10;
}
}
@@ -153,10 +146,13 @@ namespace {
/** Get grid length */
auto length() const noexcept -> size_t { return length_; }
auto pos_x(Pos const& pos) const noexcept -> size_t { return pos.first; }
auto pos_y(Pos const& pos) const noexcept -> size_t { return pos.second; }
/** Add a square to the grid. */
auto add(Square const &sq) noexcept -> void {
for (auto i = sq.x(); i < sq.x() + sq.length(); ++i) {
for (auto j = sq.y(); j < sq.y() + sq.length(); ++j) {
for (auto i = pos_x(sq.pos()); i < pos_x(sq.pos()) + sq.length(); ++i) {
for (auto j = pos_y(sq.pos()); j < pos_y(sq.pos()) + sq.length(); ++j) {
set(i, j, filled);
}
}
@@ -164,8 +160,8 @@ namespace {
/** Clear a square from the grid. */
auto clear(Square const &sq) noexcept -> void {
for (auto i = sq.x(); i < sq.x() + sq.length(); ++i) {
for (auto j = sq.y(); j < sq.y() + sq.length(); ++j) {
for (auto i = pos_x(sq.pos()); i < pos_x(sq.pos()) + sq.length(); ++i) {
for (auto j = pos_y(sq.pos()); j < pos_y(sq.pos()) + sq.length(); ++j) {
set(i, j, empty);
}
}
@@ -184,31 +180,30 @@ namespace {
* This means we only need to look for the first non-clear position along the
* current row.
*/
auto b = x(pos);
auto b = pos_x(pos);
// Make sure we don't go looking in the next row.
auto e = std::min(x(pos) + n, length_);
auto e = std::min(pos_x(pos) + n, length_);
while (b < e) {
if (grid_[b + y(pos) * length_] != empty) { break; }
if (grid_[b + pos_y(pos) * length_] != empty) { break; }
++b;
}
// Check that this length fits vertically as well.
auto len = b - x(pos);
auto ye = std::min(y(pos) + len, length_);
return ye - y(pos);
auto len = b - pos_x(pos);
auto ye = std::min(pos_y(pos) + len, length_);
return ye - pos_y(pos);
}
/** Get the next position to check. n is the size of the square we just
* added.
*/
auto next_pos(Pos const &pos, size_t n) const noexcept -> Pos {
auto const b = grid_.begin() + x(pos) + n + y(pos) * length_;
auto const b = grid_.begin() + pos_x(pos) + n + pos_y(pos) * length_;
auto const p = std::find(b, grid_.end(), empty);
auto const v = p - grid_.begin();
return std::make_pair(v % length_, v / length_);
}
private:
/** Set the grid position (x, y) to the character c.
*
* It is an error if (x, y) is already set to c - as that means we have overlapping
@@ -283,7 +278,7 @@ namespace {
sqs.pop_back();
grid.clear(sq);
++avail_sqs[sq.length()];
pos = std::make_pair(sq.x(), sq.y());
pos = sq.pos();
idx = sq.length() - 1;
continue;
}
@@ -303,7 +298,7 @@ namespace {
idx = grid.largest_square(pos, n);
// Have we reached the end? If so success!
if (x(pos) == 0 && y(pos) == grid.length()) { break; }
if (grid.pos_x(pos) == 0 && grid.pos_y(pos) == grid.length()) { break; }
}
return Results(length, sqs);