Don't immediately store pretty squares

The initial implementation of the code stored squares in the grid in a
"pretty" form.  This is a complicated bit of code and slowed down the
code slightly.

Now we just store the size of the current square in the grid.  This
reduces the code complexity, and offers a slight performance
improvement.

We still output a prettified version of the grid, as we can generate
that from a grid populated with just square sizes.
This commit is contained in:
2025-09-01 17:43:51 +02:00
parent 9cbc6c4cbc
commit 706baf9048

77
main.cc
View File

@@ -11,6 +11,7 @@
#include <string_view> #include <string_view>
#include <vector> #include <vector>
#include <iostream> #include <iostream>
#include <set>
/** (x, y) pair storing a position. */ /** (x, y) pair storing a position. */
using Pos = std::pair<int, int>; using Pos = std::pair<int, int>;
@@ -76,35 +77,9 @@ struct Grid {
/** Add a square to the grid. */ /** Add a square to the grid. */
auto add(Square const &sq) noexcept -> void { auto add(Square const &sq) noexcept -> void {
switch (sq.length()) { for (auto i = sq.x(); i < sq.x() + sq.length(); ++i) {
case 1: set(sq.x(), sq.y(), '*'); for (auto j = sq.y(); j < sq.y() + sq.length(); ++j) {
break; set(i, j, sq.length());
case 2: set(sq.x(), sq.y(), '+');
set(sq.x() + 1, sq.y(), '+');
set(sq.x(), sq.y() + 1, '+');
set(sq.x() + 1, sq.y() + 1, '+');
break;
default: {
auto n = sq.length();
set(sq.x(), sq.y(), '+');
set(sq.x() + n - 1, sq.y(), '+');
set(sq.x(), sq.y() + n - 1, '+');
set(sq.x() + n - 1, sq.y() + n - 1, '+');
for (int i = 1; i < n - 1; ++i) {
set(sq.x() + i, sq.y(), '-');
set(sq.x() + i, sq.y() + n - 1, '-');
set(sq.x(), sq.y() + i, '|');
for (int j = 1; j < n - 1; ++j) {
set(sq.x() + j, sq.y() + i, ' ');
}
set(sq.x() + n - 1, sq.y() + i, '|');
}
int i = sq.x() + n - 1;
while (n != 0) {
set(--i, sq.y() + 1, '0' + (n % 10));
n /= 10;
}
} }
} }
} }
@@ -118,6 +93,15 @@ struct Grid {
} }
} }
auto prettify() noexcept -> void {
for (auto idx = 0; idx < grid_.size(); ++idx) {
if (grid_[idx] < 32) {
auto const pos = std::make_pair(idx % length_, idx / length_);
prettify_sq(Square(pos, grid_[idx]));
}
}
}
/** Output the grid. */ /** Output the grid. */
auto output() const -> void { auto output() const -> void {
for (auto idx = 0; idx < length_ * length_; idx += length_) { for (auto idx = 0; idx < length_ * length_; idx += length_) {
@@ -162,6 +146,40 @@ struct Grid {
} }
private: private:
auto prettify_sq(Square const &sq) noexcept -> void {
switch (sq.length()) {
case 1: set(sq.x(), sq.y(), '*');
break;
case 2: set(sq.x(), sq.y(), '+');
set(sq.x() + 1, sq.y(), '+');
set(sq.x(), sq.y() + 1, '+');
set(sq.x() + 1, sq.y() + 1, '+');
break;
default: {
auto n = sq.length();
set(sq.x(), sq.y(), '+');
set(sq.x() + n - 1, sq.y(), '+');
set(sq.x(), sq.y() + n - 1, '+');
set(sq.x() + n - 1, sq.y() + n - 1, '+');
for (int i = 1; i < n - 1; ++i) {
set(sq.x() + i, sq.y(), '-');
set(sq.x() + i, sq.y() + n - 1, '-');
set(sq.x(), sq.y() + i, '|');
for (int j = 1; j < n - 1; ++j) {
set(sq.x() + j, sq.y() + i, ' ');
}
set(sq.x() + n - 1, sq.y() + i, '|');
}
int i = sq.x() + n - 1;
while (n != 0) {
set(--i, sq.y() + 1, '0' + (n % 10));
n /= 10;
}
}
}
}
/** Set the grid position (x, y) to the character c. /** 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 * It is an error if (x, y) is already set to c - as that means we have overlapping
@@ -229,6 +247,7 @@ auto find_solution(int n) -> Grid {
Avail avail_sqs; Avail avail_sqs;
for (auto i = 0; i <= n; ++i) { avail_sqs.push_back(i); } for (auto i = 0; i <= n; ++i) { avail_sqs.push_back(i); }
find_solution_impl(grid, n, std::make_pair(0, 0), avail_sqs); find_solution_impl(grid, n, std::make_pair(0, 0), avail_sqs);
grid.prettify();
return grid; return grid;
} }