Code cleanup

src/HiddenLines.cpp

@@ -17,40 +17,6 @@ HL::HL()
 	lines = construct_HWprob();
 }
 
-std::map<int, Line> HL::get_map()
-{
-	return line_holder;
-}
-
-
-void HL::print_sol()
-{
-	auto sol = get_sol();
-	for(auto itr = sol.begin(); itr != sol.end(); itr++){
-		double start_range = std::get<0>(std::get<1>(*itr));
-		std::string start_print = std::to_string(start_range);
-		if(start_range == std::numeric_limits<double>::lowest())
-			start_print = "-inf";
-
-		double stop_range = std::get<1>(std::get<1>(*itr));
-		std::string stop_print = std::to_string(stop_range);
-		if(stop_range == std::numeric_limits<double>::max())
-			stop_print = "inf";
-
-		if (start_range == stop_range)
-			continue;
-		std::cout << "Line ID " << std::get<0>(*itr) << " visible from x=" <<
-			start_print << " to x=" << stop_print << std::endl;
-	}
-
-	std::cout << std::endl;
-	auto lines = get_lines();
-	for(Line line : lines){
-		std::cout << "Line ID " << line.get_id() << " visible from x=" <<
-			line.get_vis_start() << " to x=" << line.get_vis_end() << std::endl;
-	}
-}
-
 void print_sol(std::vector<Line>& lines)
 {
 	for(auto itr = lines.begin(); itr != lines.end(); itr++){
@@ -75,22 +41,24 @@ void print_sol(std::vector<Line>& lines)
 //Divide and Conquer Strategy using recursive call to divide ls and merge using merge()
 std::vector<Line> HL::gen_sol(std::vector<Line>& ls){
 	HL inst = *this;
-	auto line_holder = inst.get_map();
 
+	//Case 1: We need to divide more
 	if (ls.size() > 2){
 		//Create left and right half sets
 		int split = ceil(ls.size()/2);
 		std::vector<Line> lh;
 		std::vector<Line> rh;
 
-		//No index access for sets
+		//Get iterator for the split point location
 		auto end_itr = ls.begin();
 		std::advance(end_itr, split);
 
+		//Create left half
 		for(std::vector<Line>::iterator itr = ls.begin(); itr != end_itr; itr++){
 			lh.push_back(*itr);
 		}
 
+		//Create right half
 		for(std::vector<Line>::iterator itr = end_itr; itr != ls.end(); itr++){
 			rh.push_back(*itr);
 		}
@@ -98,31 +66,22 @@ std::vector<Line> HL::gen_sol(std::vector<Line>& ls){
 		//Recursive call
 		auto merged = merge(inst.gen_sol(lh), inst.gen_sol(rh));
 
-		for (std::vector<Line>::iterator itr = merged.begin(); itr != merged.end(); itr++){
-			Line l1 = *itr;
-
-			std::vector<std::pair<int, std::pair<double, double>>>::iterator it = std::find_if(sol.begin(), sol.end(),
-		    	[l1](const std::pair<int, std::pair<double, double>>& p )
-		    	{ return (std::get<0>(p) == l1.get_id()); });
-
-			if(it != sol.end())
-				*it = std::make_pair(l1.get_id(), std::make_pair(l1.get_vis_start(), l1.get_vis_end()));
-			else
-				sol.push_back(std::make_pair(l1.get_id(), std::make_pair(l1.get_vis_start(), l1.get_vis_end())));
-		}
-
 		return  merged;
 	}
 
 	//Set with 2 lines is a base case: both are visible at +-inf respectively, and intersection is where they change 
 	//visibility
 	else if (ls.size() == 2){
+		//Get non-const iterators to the beginning and end of our vector
 		std::vector<Line>::iterator bit = ls.begin();
 		std::vector<Line>::iterator eit = std::prev(ls.end());
 		Line l1 = *(bit);
 		Line l2 = *(eit);
-		double isec = (l2.get_ycept() - l1.get_ycept())/(l1.get_slope() - l2.get_slope());
 
+		//Get intersection of our two lines
+		double isec = l1.get_isec(l2);
+
+		//If Line 1 has smaller slope, its visibility end in comparison to Line 2 is the intersection. Vice versa for Line 2.
 		if (l1.get_slope() < l2.get_slope()){
 			l1.set_vis_end(isec);
 			*bit = l1;
@@ -136,14 +95,10 @@ std::vector<Line> HL::gen_sol(std::vector<Line>& ls){
 			*eit = l2;
 		}
 
-		//Insert partial solutions
-		sol.push_back(std::make_pair(l1.get_id(), std::make_pair(l1.get_vis_start(), l1.get_vis_end())));
-		sol.push_back(std::make_pair(l2.get_id(), std::make_pair(l2.get_vis_start(), l2.get_vis_end())));
-
 		return ls;
 	}
 
-	//Set with 1 line: Just return
+	//Set with 1 line: Just return - no comparisons to make at this point.
 	else{
 		return ls;
 	}
@@ -187,10 +142,6 @@ std::vector<Line> HL::construct_HWprob(){
     	Line newline = Line(slope, ycept);
     	newline.set_id();
     	sorted_lines.insert(newline);
-
-    	auto line_holder = get_map();
-    	//line_holder[newline.get_id()] = newline;
-    	line_holder.insert(std::pair<int, Line> (newline.get_id(), newline));
     }
 
     //Copy set to vector
@@ -220,6 +171,7 @@ std::vector<Line> HL::construct_HWprob(){
 std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh){
 	std::vector<Line> merged;
 
+	//Get non-const iterators to the start of both vectors
 	std::vector<Line>::iterator litr = lh.begin();
 	std::vector<Line>::iterator ritr = rh.begin();
 
@@ -246,11 +198,13 @@ std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh){
 			if (l1.get_ycept() > l2.get_ycept()){
 				l2.set_vis_start(0);
 				l2.set_vis_end(0);
+				*ritr = l2;
 				merged.push_back(l1);
 			}
 			else{
 				l1.set_vis_start(0);
 				l1.set_vis_end(0);
+				*litr = l1;
 				merged.push_back(l2);
 			}
 
@@ -289,33 +243,33 @@ std::vector<Line> HL::get_lines(){
 	return lines;
 }
 
-std::vector<std::pair<int, std::pair<double, double>>> HL::get_sol() const{
-	return sol;
-}
-
-void HL::set_sol(std::vector<std::pair<int, std::pair<double, double>>> &new_sol)
-{
-	sol = new_sol;
-}
-
 std::vector<Line> remove_invis(std::vector<Line> &merged){
-	std::vector<Line> tmp_vis;
-	tmp_vis.push_back(merged.front());
-	merged.erase(merged.begin());
-	tmp_vis.push_back(merged.front());
-	merged.erase(merged.begin());
 
+	//Create separate visible line holder
+	std::vector<Line> tmp_vis;
+
+	//Since we call this function from a merge, we can safely add two elements.
+	tmp_vis.push_back(merged.front());
+	merged.erase(merged.begin());
+	tmp_vis.push_back(merged.front());
+	merged.erase(merged.begin());
 	int num_vis = 2;
 
-	for(Line line : merged){
+	//Loop through the remainder of the original vector
+	for(Line &line : merged){
+		//Pull out the back two lines
 		Line last = tmp_vis.at(num_vis -1);
 		Line seclast = tmp_vis.at(num_vis -2);
 
+		//Intersection of our "known" visible lines vs the intersection of the 2nd to last vis line and the original vec
 		double vis_isec = last.get_isec(seclast);
 		double merg_isec = line.get_isec(seclast);
+
 		while(merg_isec < vis_isec){
+			//line intersects before the last line, and since line slope > last line slope, remove it
 			tmp_vis.erase(tmp_vis.begin() + (num_vis -1));
 			num_vis--;
+			line.set_vis_start(merg_isec);
 
 			if(num_vis == 1)
 				break;

src/HiddenLines.h

@@ -10,22 +10,13 @@ class HL
 	public:
 		HL();
 
-		void print_sol();
-
 		std::vector<Line> gen_sol(std::vector<Line>& ls);
 		std::vector<Line> construct_HWprob();
 		
 		std::vector<Line> get_lines();
-		std::vector<std::pair<int, std::pair<double, double>>> get_sol() const;
-		void set_sol(std::vector<std::pair<int, std::pair<double, double>>> &new_sol);
-
-		std::map<int, Line> get_map();
 
 	private:
-		//Solution is in form (Line ID, (vis_start, vis_end))
-		std::vector<std::pair<int, std::pair<double, double>>> sol;
 		std::vector<Line> lines;
-		std::map<int, Line> line_holder;
 };
 
 std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh);