diff --git a/delaunay.h b/delaunay.h
index a02f074..a6513b4 100644
--- a/delaunay.h
+++ b/delaunay.h
@@ -131,7 +131,8 @@ void triangulation(std::vector<vertex2dc> &in_verts, std::vector<triangle> &out_
 	assit_vert.push_back(tmp_vert);
 
 	triangle *tmp_tri = nullptr;
-	std::vector<triangle*>  exist_tri, cnst_tri, remain_tri;
+	std::vector<triangle*>  exist_tri, cnst_tri;
+	std::vector<triangle*>::iterator t_iter;
 
 	tmp_tri = new triangle(assit_vert[0], assit_vert[1], assit_vert[2]); // order the vertex anti-clock wise
 	exist_tri.push_back(tmp_tri);
@@ -147,25 +148,22 @@ void triangulation(std::vector<vertex2dc> &in_verts, std::vector<triangle> &out_
 	std::vector<edge>::iterator e_iter;
 	for (int i = 0; i < in_verts.size(); ++i)
 	{
-		// determine triangles that include the point and add the triangle to the cnst_tri
-		// Otherwise, add the triangle to the remain_tri
-		// this is the part that could take a lot of time if we are working with a large amount of points
-		// We will fix this later
+		// determine triangles that include the point and add the triangle to the cnst_tri and remove the triangle from exist_tri
+		// this is the part that could take a lot of time if we are working with a large amount of points. We will fix this later
 		cnst_tri.clear();
-		remain_tri.clear();
-		for (int t = 0; t < exist_tri.size(); ++t)
+		for (t_iter = exist_tri.begin(); t_iter != exist_tri.end(); )
 		{
-			dist = (exist_tri[t]->cx - in_verts[i].x) * (exist_tri[t]->cx - in_verts[i].x) + 
-				(exist_tri[t]->cy - in_verts[i].y) * (exist_tri[t]->cy - in_verts[i].y);
+			tmp_tri = *t_iter;
 
-			if ((dist - exist_tri[t]->cr) <= ZERO) // Points on the circumcircle are also included
+			dist = (tmp_tri->cx - in_verts[i].x) * (tmp_tri->cx - in_verts[i].x) + 
+				(tmp_tri->cy - in_verts[i].y) * (tmp_tri->cy - in_verts[i].y);
+
+			if ((dist - tmp_tri->cr) <= ZERO) // Points on the circumcircle are also included
 			{
-				cnst_tri.push_back(exist_tri[t]);
-			}
-			else
-			{
-				remain_tri.push_back(exist_tri[t]);
+				t_iter = exist_tri.erase(t_iter);
+				cnst_tri.push_back(tmp_tri);
 			}
+			else t_iter++;
 		}
 
 		// loop to remove duplicate edges
@@ -195,24 +193,22 @@ void triangulation(std::vector<vertex2dc> &in_verts, std::vector<triangle> &out_
 			}
 		}
 
-		exist_tri.clear();
-		exist_tri.reserve(remain_tri.size() + cnst_edge.size());
-		// copy remain_tri to exist_tri
-		for (int r = 0; r < remain_tri.size(); ++r)
-		{
-			exist_tri.push_back(remain_tri[r]);
-		}
-
 		// construct new triangles and add to exist_tri
 		for (int c = 0; c < cnst_edge.size(); ++c)
 		{
 			tmp_tri = new triangle(cnst_edge[c].vert[0], cnst_edge[c].vert[1], &in_verts[i]); // order the vertex anti-clock wise
 			exist_tri.push_back(tmp_tri);
 		}
+
+		// destroy memories used by cnst_edge
+		for (int c = 0; c < cnst_tri.size(); ++c)
+		{
+			tmp_tri = cnst_tri[c];
+			delete tmp_tri; tmp_tri = nullptr;
+		}
 	}
 
 	// remove any triangles has an assistant vertex from exist_tri
-	std::vector<triangle*>::iterator t_iter;
 	for (t_iter = exist_tri.begin(); t_iter != exist_tri.end(); )
 	{
 		tmp_tri = *t_iter;
@@ -220,14 +216,14 @@ void triangulation(std::vector<vertex2dc> &in_verts, std::vector<triangle> &out_
 			tmp_tri->vert[1] == assit_vert[0] || tmp_tri->vert[1] == assit_vert[1] || tmp_tri->vert[1] == assit_vert[2] || tmp_tri->vert[1] == assit_vert[3] || 
 			tmp_tri->vert[2] == assit_vert[0] || tmp_tri->vert[2] == assit_vert[1] || tmp_tri->vert[2] == assit_vert[2] || tmp_tri->vert[2] == assit_vert[3])
 		{
-			// destroy the memory located and remove from the vector
+			// destroy the memories located and remove from the vector
 			t_iter = exist_tri.erase(t_iter);
 			delete tmp_tri; tmp_tri = nullptr;
 		}
 		else t_iter++;
 	}
 
-	// copy exist_tri to out_tris and destroy memory located
+	// copy exist_tri to out_tris and destroy memories located
 	out_tris.resize(exist_tri.size());
 	for (int i = 0; i < exist_tri.size(); ++i)
 	{
@@ -235,7 +231,7 @@ void triangulation(std::vector<vertex2dc> &in_verts, std::vector<triangle> &out_
 		delete exist_tri[i]; exist_tri[i] = nullptr;
 	}
 
-	// destroy memory located for assit_vert
+	// destroy memories located for assit_vert
 	for (int i = 0; i < 4; ++i)
 	{
 		delete assit_vert[i]; assit_vert[i] = nullptr;