From 78b3dda9017aab8c9031ce67eb30f29036e5df24 Mon Sep 17 00:00:00 2001
From: Shine wOng <1551885@tongji.edu.cn>
Date: Sun, 9 Jun 2019 14:25:28 +0800
Subject: [PATCH] implement BinNode<T>::succ(), with all tests passed.

---
 thu_dsa/chp5/binNode.h       | 17 ++++++++++++++++-
 thu_dsa/chp5/testBinTree.cpp | 21 +++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/thu_dsa/chp5/binNode.h b/thu_dsa/chp5/binNode.h
index 9ba252a..002f7a9 100644
--- a/thu_dsa/chp5/binNode.h
+++ b/thu_dsa/chp5/binNode.h
@@ -26,11 +26,12 @@ public:
 	//constructor
 	BinNode() : parent(nullptr), leftChild(nullptr), rightChild(nullptr), height(0), color(0), npl(0) {};
 	BinNode(T const &val) : parent(nullptr), leftChild(nullptr), rightChild(nullptr), data(val), height(0), color(0), npl(0) {};
+	BinNode(T const &val, BinNodePosi(T) p): parent(p), leftChild(nullptr), rightChild(nullptr), data(val), height(0), color(0), npl(0) {};
 
 	int size() const;									//compute the size of the tree rooted at current node
 	BinNodePosi(T) insertAsLC(T const &val);			//always assume that this.leftChild  == nullptr
 	BinNodePosi(T) insertAsRC(T const &val);			//always assume that this.rightChild == nullptr
-	BinNodePosi(T) succ() const;						//return the direct successor of current node
+	BinNodePosi(T) succ();						//return the direct successor of current node
 
 	//tree traversal
 	template <typename VST> void preOrder_Re(VST &visit);
@@ -105,6 +106,20 @@ BinNodePosi(T) BinNode<T>::insertAsRC(T const &val){
 	return currNode;
 }
 
+template <typename T>
+BinNodePosi(T) BinNode<T>::succ(){
+	BinNodePosi(T) succ;
+	if(rightChild){
+		succ = rightChild;
+		while (succ->leftChild) succ = succ->leftChild;
+	}else{
+		succ = this;
+		while(succ->parent && succ == succ->parent->rightChild) succ = succ->parent;
+		succ = succ->parent;
+	}
+	return succ;
+}
+
 //tree traversal
 
 template <typename T> template <typename VST>
diff --git a/thu_dsa/chp5/testBinTree.cpp b/thu_dsa/chp5/testBinTree.cpp
index 5d5ca4c..22ccb60 100644
--- a/thu_dsa/chp5/testBinTree.cpp
+++ b/thu_dsa/chp5/testBinTree.cpp
@@ -7,6 +7,7 @@ using std::endl;
 
 void test_insert();
 void test_size();
+void test_succ();
 void test_preTraversal();
 void test_inTraversal();
 void test_postTraversal();
@@ -17,6 +18,7 @@ int main(){
 
 	test_insert();
 	test_size();
+	test_succ();
 	test_preTraversal();
 	test_inTraversal();
 	test_postTraversal();
@@ -68,6 +70,25 @@ void test_size(){
 	assert(root->size() == 3);
 }
 
+void test_succ(){
+	//construct a binary tree
+	BinTree<int> intTree;
+	BinNodePosi(int) root = intTree.insertAsRoot(8);
+	BinNodePosi(int) left = intTree.insertAsLC(root, 7);
+	BinNodePosi(int) right = intTree.insertAsRC(root, 14);
+	BinNodePosi(int) first = intTree.insertAsLC(left, 4);
+	intTree.insertAsRC(left, 3);
+	intTree.insertAsLC(right, 12);
+	intTree.insertAsRC(right, 18);
+
+	//test succ
+	int inOrder[] = { 4, 7, 3, 8, 12, 14, 18 };
+	BinNodePosi(int) x = first;
+	for (int ix = 0; x; ++ix, x = x->succ()) {
+		assert(x->data == inOrder[ix]);
+	}
+}
+
 template <typename T>
 struct Print{
 	virtual void operator()(T const &val){