Remove invisible line function

src/HiddenLines.cpp

@@ -220,9 +220,8 @@ std::vector<Line> HL::construct_HWprob(){
 std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh){
 	std::vector<Line> merged;
 
-	std::cout << "Merging a left half of size " << lh.size() << " and a right half of size " << rh.size() << std::endl;
+	std::vector<Line>::iterator litr = lh.begin();
-	auto litr = lh.begin();
+	std::vector<Line>::iterator ritr = rh.begin();
-	auto ritr = rh.begin();
 
 	while(litr != lh.end() && ritr != rh.end()){
 		Line l1 = *litr;
@@ -235,6 +234,8 @@ std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh){
 			if(isec < l1.get_vis_end()){
 				l1.set_vis_end(isec);
 				l2.set_vis_start(isec);
+				*litr = l1;
+				*ritr = l2;
 			}
 			merged.push_back(l1);
 			//merged.push_back(l2);
@@ -263,15 +264,25 @@ std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh){
 			if(isec < l1.get_vis_start()){
 				l1.set_vis_start(isec);
 				l2.set_vis_end(isec);
+				*litr = l1;
+				*ritr = l2;
 			}
-
-			//merged.push_back(l1);
 			merged.push_back(l2);
 			ritr++;
 		}
 	}
 
-	return merged;
+	while (litr != lh.end()){
+		merged.push_back(*litr);
+		litr++;
+	}
+	while (ritr != rh.end()){
+		merged.push_back(*ritr);
+		ritr++;
+	}
+
+	//Remove invisible lines
+	return remove_invis(merged);
 }
 
 std::vector<Line> HL::get_lines(){
@@ -286,3 +297,38 @@ 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());
+
+	int num_vis = 2;
+
+	for(Line line : merged){
+		Line last = tmp_vis.at(num_vis -1);
+		Line seclast = tmp_vis.at(num_vis -2);
+
+		double vis_isec = last.get_isec(seclast);
+		double merg_isec = line.get_isec(seclast);
+		while(merg_isec < vis_isec){
+			tmp_vis.erase(tmp_vis.begin() + (num_vis -1));
+			num_vis--;
+
+			if(num_vis == 1)
+				break;
+
+			last = tmp_vis.at(num_vis -1);
+			seclast = tmp_vis.at(num_vis -2);
+			vis_isec = last.get_isec(seclast);
+			merg_isec = line.get_isec(seclast);
+		}
+
+		tmp_vis.push_back(line);
+		num_vis++;
+	}
+
+	return tmp_vis;
+}

src/HiddenLines.h

@@ -30,4 +30,6 @@ class HL
 
 std::vector<Line> merge(std::vector<Line> lh, std::vector<Line> rh);
 void print_sol(std::vector<Line>& lines);
+std::vector<Line> remove_invis(std::vector<Line> &merged);
+
 

src/Line.cpp

@@ -81,3 +81,8 @@ void Line::set_vis_end(double x)
 {
 	vis_end = x;
 }
+
+double Line::get_isec(Line &l2)
+{
+	return ((l2.get_ycept() - get_ycept())/(get_slope() - l2.get_slope()));
+}

src/Line.h

@@ -21,6 +21,8 @@ class Line
 		bool is_vis();
 		void set_id();
 		int get_id() const;
+		double get_isec(Line &l2);
+
 
 		bool operator==(const Line &l2) const;
 		bool operator<(const Line &l2) const;