Adds a random generator. Fixes some warnings. Adds some comments

include/clusters.hpp

@@ -45,4 +45,12 @@ auto all_clusters(Field const & field){
 	return ret;
 }
 
-#undef Set
+template <typename Field, typename Cluster>
+auto make_empty(Field field, Cluster const & c){
+	using namespace std;
+	for(auto&& p : c){
+		field.get(p) = 0;
+	}
+	field.collapse();
+	return field;
+}

include/field.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cassert>
 #include <utility>
 #include <array>
 #include <algorithm>
@@ -23,7 +24,7 @@ struct small_vector{
 
 // Position {0,0} is bottom left.
 // Position {W-1, H-1} is top right.
-template <size_t W, size_t H, typename T>
+template <int W, int H, typename T>
 struct Field{
 	using Position = std::pair<int, int>;
 
@@ -31,15 +32,20 @@ struct Field{
 		std::copy(std::begin(g), std::end(g), std::begin(grid));
 	}
 
+	//! \brief Returns true if p represents a valid position
 	auto valid(Position const & p) const {
 		return p.first >= 0 && p.second >= 0
 		    && p.first <  W && p.second < H;
 	}
 
+	//! \brief Returns true if p represents an empty cell
 	auto empty(Position const & p) const {
+		assert(valid(p));
 		return get(p) == 0;
 	}
 
+	//! \brief Returns all neighbors of p
+	//! Only returns valid neighbors (and p does not need to be valid)
 	auto neighbors(Position const & p) const {
 		small_vector<Position, 4> ret;
 
@@ -57,24 +63,31 @@ struct Field{
 		return ret;
 	}
 
+	//! \brief Let the block fall (all the way)
 	auto collapse(){
 		while(vcollapse());
 		while(hcollapse());
 	}
 
+	//! \brief Returns an array of all valid positions
 	auto const & all_positions() const {
 		using Indices = std::make_index_sequence<W*H>;
 		return all_positions_impl(Indices{});
 	}
 
+	//! \brief Get (mutable) value at p
 	T& get(Position const & p){
-		return grid[p.first + p.second*W];
+		assert(valid(p));
+		return grid[static_cast<size_t>(p.first + p.second*W)];
 	}
 
+	//! \brief Get value at p
 	T const& get(Position const & p) const {
-		return grid[p.first + p.second*W];
+		assert(valid(p));
+		return grid[static_cast<size_t>(p.first + p.second*W)];
 	}
 
+	//! \brief Pretty prints grid to out
 	void print(std::ostream& out) const {
 		for(auto y = H; y; --y){
 			for(auto x = 0; x < W; ++x){
@@ -86,14 +99,16 @@ struct Field{
 private:
 	std::array<T, W*H> grid;
 
+	//! \brief Helper function for all_positions()
 	template<std::size_t... I>
 	auto const & all_positions_impl(std::index_sequence<I...>) const {
-		static const std::array<const Position, W*H> ret = {
+		static const std::array<const Position, W*H> ret = {{
 			Position{I % W, I / W}...
-		};
+		}};
 		return ret;
 	}
 
+	//! \brief Single vertical collapsing step
 	auto vcollapse(){
 		using namespace std;
 		bool some_change = false;
@@ -112,6 +127,7 @@ private:
 		return some_change;
 	}
 
+	//! \brief Single horizontal collapsing step
 	auto hcollapse(){
 		using namespace std;
 		bool some_change = false;
@@ -132,7 +148,8 @@ private:
 		return some_change;
 	}
 
-	auto empty_column(size_t x){
+	//! \brief Returns true if the whole column at x is empty
+	auto empty_column(int x){
 		for(auto y = 0; y < H; ++y){
 			if(!empty({x, y})){
 				return false;
@@ -142,7 +159,8 @@ private:
 	}
 };
 
-template <size_t W, size_t H, typename T>
+//! \brief Helper function to create a field (T will be deducted)
+template <int W, int H, typename T>
 auto create_rectangular_field(std::initializer_list<T> grid){
 	return Field<W, H, T>(grid);
 }

include/generator.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "field.hpp"
+
+#include <random>
+
+namespace detail {
+	template <int W, int H, typename URNG, size_t... I>
+	auto random_field(URNG&& r, std::index_sequence<I...>){
+		std::uniform_int_distribution<int> dis(0, 4);
+		return create_rectangular_field<W, H>({
+			((void)I, dis(r))...
+		});
+	}
+}
+
+template <int W, int H, typename URNG>
+auto random_field(URNG&& r){
+	using Indices = std::make_index_sequence<W*H>;
+	return detail::random_field<W, H>(r, Indices{});
+}

include/solver.hpp

@@ -2,16 +2,6 @@
 
 #include "clusters.hpp"
 
-template <typename Field, typename Container>
-auto make_empty(Field field, Container const & c){
-	using namespace std;
-	for(auto&& p : c){
-		field.get(p) = 0;
-	}
-	field.collapse();
-	return field;
-}
-
 template <typename Field>
 auto solve(Field const & field){
 	for(auto&& p : field.all_positions()){

main.cpp

@@ -2,8 +2,10 @@
 #include "field.hpp"
 #include "clusters.hpp"
 #include "solver.hpp"
+#include "generator.hpp"
 
 #include <iostream>
+#include <random>
 #include <chrono>
 #include <thread>
 
@@ -17,35 +19,11 @@ auto is_void(Field const & field){
 
 int main(){
 	using namespace std;
-//	constexpr auto W = 10;
-//	constexpr auto H = 10;
 
-//	auto field = create_rectangular_field<W, H>({
-//		2, 1, 1, 1, 2, 1, 2, 4, 1, 2,
-//		2, 2, 2, 1, 2, 2, 1, 1, 1, 2,
-//		1, 1, 1, 1, 1, 1, 1, 2, 2, 2,
-//		2, 1, 1, 4, 2, 4, 2, 1, 2, 1,
-//		1, 1, 1, 3, 2, 2, 2, 3, 3, 4,
-//		3, 2, 2, 1, 1, 1, 2, 2, 2, 2,
-//		1, 1, 2, 1, 3, 1, 1, 4, 2, 3,
-//		1, 1, 1, 1, 3, 1, 3, 2, 1, 2,
-//		1, 1, 1, 1, 2, 4, 1, 3, 1, 2,
-//		1, 1, 1, 1, 2, 2, 1, 1, 4, 9
-//	});
+	std::random_device rd;
+	std::mt19937 gen(rd());
 
-	constexpr auto W = 9;
-	constexpr auto H = 9;
-	auto field = create_rectangular_field<W, H>({
-		2, 1, 1, 1, 2, 1, 2, 4, 1,
-		2, 2, 2, 1, 2, 2, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 2, 2,
-		2, 1, 1, 4, 2, 4, 2, 1, 2,
-		1, 1, 1, 3, 2, 2, 2, 3, 3,
-		3, 2, 2, 1, 1, 1, 2, 2, 2,
-		1, 1, 2, 1, 3, 1, 1, 4, 2,
-		1, 1, 1, 1, 3, 1, 3, 2, 1,
-		1, 1, 1, 1, 2, 4, 1, 3, 9
-	});
+	auto field = random_field<5, 5>(gen);
 
 	field.print(std::cout);