diff --git a/ArchitectureColoredPainting/ShortCutTree.cpp b/ArchitectureColoredPainting/ShortCutTree.cpp
index 4717a3e..03180c1 100644
--- a/ArchitectureColoredPainting/ShortCutTree.cpp
+++ b/ArchitectureColoredPainting/ShortCutTree.cpp
@@ -46,11 +46,10 @@ void ShortCutTree::monotonization(vector<PointVector>& inL, vector<LinePtr>& out
 
 void ShortCutTree::generateShortCutsegmentement(ShortCutNode& nowTreeNode) {
 	Point p = {0, 0};
-	vector<int> v;
+	set<pair<int, int> > pointSet;
 	for (int & lineIndex : nowTreeNode.lineSet) {
 		int type = allLine[lineIndex]->judgeBoundIntersection(nowTreeNode.bound.z(), nowTreeNode.bound.y(), nowTreeNode.bound.w(), false), lineIndexBegin, lineIndexEnd;
 		if (type >= 2) {
-			v.push_back(numLine);
 			if (type == 2) {
 				p = allLine[lineIndex]->getEnd();
 			}
@@ -59,25 +58,33 @@ void ShortCutTree::generateShortCutsegmentement(ShortCutNode& nowTreeNode) {
 			}
 			lineIndexBegin = getPointIndex({ p.x, nowTreeNode.bound.w() });
 			lineIndexEnd = getPointIndex(p);
-			lineIndexs.push_back(lineIndexBegin);
-			lineIndexs.push_back(lineIndexBegin);
-			lineIndexs.push_back(lineIndexEnd);
-			lineIndexs.push_back(lineIndexEnd);
-			numLine++;
+			auto iter = pointSet.find({ lineIndexBegin, lineIndexEnd });
+			if (iter != pointSet.end()) {
+				pointSet.erase(iter);
+			}
+			else {
+				pointSet.insert({ lineIndexBegin, lineIndexEnd });
+			}
 		}
-	}	
+	}
 	if (nowTreeNode.windingIncrement != 0) {
-		v.push_back(numLine);
 		int lineIndexBegin = getPointIndex({ nowTreeNode.bound.z(), nowTreeNode.bound.y()});
 		int lineIndexEnd = getPointIndex({ nowTreeNode.bound.z(), nowTreeNode.bound.w() });
-		lineIndexs.push_back(lineIndexBegin);
-		lineIndexs.push_back(lineIndexBegin);
-		lineIndexs.push_back(lineIndexEnd);
-		lineIndexs.push_back(lineIndexEnd);
-		numLine++;
+		auto iter = pointSet.find({ lineIndexBegin, lineIndexEnd });
+		if (iter != pointSet.end()) {
+			pointSet.erase(iter);
+		}
+		else {
+			pointSet.insert({ lineIndexBegin, lineIndexEnd });
+		}
 	}
-	for (int& lineIndex : v) {
-		nowTreeNode.lineSet.push_back(lineIndex);
+	for (auto& iter : pointSet) {
+		nowTreeNode.lineSet.push_back(numLine);
+		lineIndexs.push_back(iter.first);
+		lineIndexs.push_back(iter.first);
+		lineIndexs.push_back(iter.second);
+		lineIndexs.push_back(iter.second);
+		numLine++;
 	}
 }
 
diff --git a/ArchitectureColoredPainting/ShortCutTree.h b/ArchitectureColoredPainting/ShortCutTree.h
index d9a2527..59ee04f 100644
--- a/ArchitectureColoredPainting/ShortCutTree.h
+++ b/ArchitectureColoredPainting/ShortCutTree.h
@@ -3,10 +3,12 @@
 #include "StraightLine.h"
 #include "BvhTree.h"
 #include <queue>
+#include <set>
 
 using std::queue;
 using std::map;
 using std::for_each;
+using std::set;
 
 struct ShortCutNode {
 	typedef vector<Point> vectorPoint;