One of our C++ class homework for practicing smart pointers. I implemented both smart pointer version and raw pointer version.
The basic problem is to write a binary tree data structure with "next" pointers.
For example,
Raw Pointer Version
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#include <iostream>
#include <memory>
#include <math.h>
#include <queue>
using namespace std;
class node {
public:
int value;
shared_ptr<node> right;
shared_ptr<node> l_child;
shared_ptr<node> r_child;
node() {}
node(int i) { value = i; }
};
class tree {
public:
shared_ptr<node> root;
int level;
tree() { level = 0; }
//Implement all member functions below
tree(int n);//constructor for n-level tree
//and initilize values as shown in the diagram; 0, 1, 2, ...
//Note that root node is at level 1 and its value will be initialized to 0
tree(const tree &T);//copy constructor
~tree();//destructor
tree(tree &&T); //move constructor
tree(const initializer_list<int> &V);//The first number in V is tree level;
//the rest are values from top to bottom and from left to right
//For example, to create the tree with n=3 in the diagram,
//tree T1 = {3, 0,1,2,3,4,5,6}; //where the first 3 is tree level, and the rest are values
void operator= (const tree &R);//L-value operator=
void operator= (tree &&R); //R-value operator=
tree ThreeTimes(); //return a tree with all node value being three times
friend ostream & operator<<(ostream &str, const tree &T);
int sum(shared_ptr<node> p);//sum of node values in sub-tree rooted at p
void delete_level(int i); // Delete nodes at level i. Some nodes at level(s) higher
//than i will also be deleted accordingly. As described in class. (Also see the
//example in the main function.)
shared_ptr<node> find(int i); //find the first node with value i and return
//its address; if not found, return nullptr;
};
// In the homework, I use Level-Order Traversal to treverse the tree.
tree::tree(int n) : tree() {
level = n;
shared_ptr<node> prev = nullptr;
queue<shared_ptr<node>> que;
root = make_shared<node>(0);
que.push(root);
while (n--) {
int size = que.size();
while (size--) {
shared_ptr<node> cur = que.front();
if (prev)
prev->right = cur;
prev = cur;
if (n) {
que.push(cur->l_child = make_shared<node>(cur->value * 2 + 1));
que.push(cur->r_child = make_shared<node>(cur->value * 2 + 2));
}
que.pop();
}
}
prev->right = root;
}
tree::tree(const tree& that) : tree() {
level = that.level;
int n = level;
shared_ptr<node> prev = nullptr;
queue<shared_ptr<node>> que1;
queue<shared_ptr<node>> que2;
root = make_shared<node>(that.root->value);
que1.push(root);
que2.push(that.root);
while (n--) {
int size = que1.size();
while (size--) {
shared_ptr<node> cur1 = que1.front();
shared_ptr<node> cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = make_shared<node>(cur2->l_child->value));
que1.push(cur1->r_child = make_shared<node>(cur2->r_child->value));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = root;
}
tree::tree(tree&& that) {
level = that.level;
that.level = 0;
root = that.root;
that.root = nullptr;
}
void tree::operator=(const tree& that) {
this->~tree();
level = that.level;
int n = level;
shared_ptr<node> prev = nullptr;
queue<shared_ptr<node>> que1;
queue<shared_ptr<node>> que2;
root = make_shared<node>(that.root->value);
que1.push(root);
que2.push(that.root);
while (n--) {
int size = que1.size();
while (size--) {
shared_ptr<node> cur1 = que1.front();
shared_ptr<node> cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = make_shared<node>(cur2->l_child->value));
que1.push(cur1->r_child = make_shared<node>(cur2->r_child->value));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = root;
}
void tree::operator=(tree&& that) {
this->~tree();
level = that.level;
that.level = 0;
root = that.root;
that.root = nullptr;
}
tree::tree(const initializer_list<int>& V) : tree(*V.begin()) {
// Replace value with values in the initializer list
const int* p = V.begin();
shared_ptr<node> prev = root;
do {
prev->value = p[prev->value + 1];
prev = prev->right;
} while (prev != root);
}
tree tree::ThreeTimes() {
tree ret;
ret.level = level;
int n = level;
shared_ptr<node> prev = nullptr;
queue<shared_ptr<node>> que1;
queue<shared_ptr<node>> que2;
ret.root = make_shared<node>(root->value * 3);
que1.push(ret.root);
que2.push(root);
while (n--) {
int size = que1.size();
while (size--) {
shared_ptr<node> cur1 = que1.front();
shared_ptr<node> cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = make_shared<node>(cur2->l_child->value * 3));
que1.push(cur1->r_child = make_shared<node>(cur2->r_child->value * 3));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = ret.root;
return ret;
}
tree::~tree() {
if (!root)
return;
shared_ptr<node> cur = root;
while (cur->right != root)
cur = cur->right;
cur->right.reset();
}
ostream& operator<<(ostream& os, const tree &obj) {
shared_ptr<node> cur = obj.root;
do {
os << cur->value << ' ';
cur = cur->right;
} while (cur != obj.root);
return os;
}
int tree::sum(shared_ptr<node> p) {
int result = 0;
queue<shared_ptr<node>> que;
que.push(p);
while (!que.empty()) {
shared_ptr<node> cur = que.front();
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
result += cur->value;
que.pop();
}
return result;
}
void tree::delete_level(int i) {
queue<shared_ptr<node>> que;
que.push(root);
int levelCount = 0;
while (!que.empty()) {
int size = que.size();
++levelCount;
while (size--) {
shared_ptr<node> cur = que.front();
if (levelCount == i - 1) {
shared_ptr<node> l = cur->l_child;
cur->l_child = l->l_child;
l.reset();
shared_ptr<node> r = cur->r_child;
cur->r_child = r->l_child;
r.reset();
}
else {
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
}
que.pop();
}
}
shared_ptr<node> prev = nullptr;
que.push(root);
while (!que.empty()) {
int size = que.size();
while (size--) {
shared_ptr<node> cur = que.front();
if (prev)
prev->right = cur;
prev = cur;
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
que.pop();
}
}
prev->right = root;
}
shared_ptr<node> tree::find(int i) {
shared_ptr<node> cur = root;
while (cur->right != root)
if (cur->value == i)
return cur;
else
cur = cur->right;
return cur->value == i ? cur : nullptr;
}
Smart Pointer Version
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#include <iostream>
#include <memory>
#include <math.h>
#include <queue>
using namespace std;
class node {
public:
int value;
node* right;
node* l_child;
node* r_child;
node() { right = l_child = r_child = nullptr; }
node(int i) { right = l_child = r_child = nullptr; value = i; }
};
class tree {
public:
node* root;
int level;
tree() { root = nullptr; level = 0; }
//Implement all member functions below
tree(int n);//constructor for n-level tree
//and initilize values as shown in the diagram; 0, 1, 2, ...
//Note that root node is at level 1 and its value will be initialized to 0
tree(const tree &T);//copy constructor
~tree();//destructor
tree(tree &&T); //move constructor
tree(const initializer_list<int> &V);//The first number in V is tree level;
//the rest are values from top to bottom and from left to right
//For example, to create the tree with n=3 in the diagram,
//tree T1 = {3, 0,1,2,3,4,5,6}; //where the first 3 is tree level, and the rest are values
void operator= (const tree &R);//L-value operator=
void operator= (tree &&R); //R-value operator=
tree ThreeTimes(); //return a tree with all node value being three times
friend ostream & operator<<(ostream &str, const tree &T);
int sum(node* p);//sum of node values in sub-tree rooted at p
void delete_level(int i); // Delete nodes at level i. Some nodes at level(s) higher
//than i will also be deleted accordingly. As described in class. (Also see the
//example in the main function.)
node* find(int i); //find the first node with value i and return
//its address; if not found, return nullptr;
void recursiveDelete(node* p);
};
// In the homework, I use Level-Order Traversal to treverse the tree.
tree::tree(int n) : tree() {
level = n;
node* prev = nullptr;
queue<node*> que;
root = new node(0);
que.push(root);
while (n--) {
int size = que.size();
while (size--) {
node* cur = que.front();
if (prev)
prev->right = cur;
prev = cur;
if (n) {
que.push(cur->l_child = new node(cur->value * 2 + 1));
que.push(cur->r_child = new node(cur->value * 2 + 2));
}
que.pop();
}
}
prev->right = root;
}
tree::tree(const tree& that) : tree() {
level = that.level;
int n = level;
node* prev = nullptr;
queue<node*> que1;
queue<node*> que2;
root = new node(that.root->value);
que1.push(root);
que2.push(that.root);
while (n--) {
int size = que1.size();
while (size--) {
node* cur1 = que1.front();
node* cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = new node(cur2->l_child->value));
que1.push(cur1->r_child = new node(cur2->r_child->value));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = root;
}
tree::tree(tree&& that) {
level = that.level;
that.level = 0;
root = that.root;
that.root = nullptr;
}
void tree::operator=(const tree& that) {
this->~tree();
level = that.level;
int n = level;
node* prev = nullptr;
queue<node*> que1;
queue<node*> que2;
root = new node(that.root->value);
que1.push(root);
que2.push(that.root);
while (n--) {
int size = que1.size();
while (size--) {
node* cur1 = que1.front();
node* cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = new node(cur2->l_child->value));
que1.push(cur1->r_child = new node(cur2->r_child->value));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = root;
}
void tree::operator=(tree&& that) {
this->~tree();
level = that.level;
that.level = 0;
root = that.root;
that.root = nullptr;
}
tree::tree(const initializer_list<int>& V) : tree(*V.begin()) {
// Replace value with values in the initializer list
const int* p = V.begin();
node* prev = root;
do {
prev->value = p[prev->value + 1];
prev = prev->right;
} while (prev != root);
}
tree tree::ThreeTimes() {
tree ret;
ret.level = level;
int n = level;
node* prev = nullptr;
queue<node*> que1;
queue<node*> que2;
ret.root = new node(root->value * 3);
que1.push(ret.root);
que2.push(root);
while (n--) {
int size = que1.size();
while (size--) {
node* cur1 = que1.front();
node* cur2 = que2.front();
if (prev)
prev->right = cur1;
prev = cur1;
if (n) {
que1.push(cur1->l_child = new node(cur2->l_child->value * 3));
que1.push(cur1->r_child = new node(cur2->r_child->value * 3));
que2.push(cur2->l_child);
que2.push(cur2->r_child);
}
que1.pop();
que2.pop();
}
}
prev->right = ret.root;
return ret;
}
tree::~tree() {
if (!root)
return;
node* prev = nullptr;
node* cur = root;
do {
prev = cur;
cur = cur->right;
delete(prev);
} while (cur != root);
}
ostream& operator<<(ostream& os, const tree &obj) {
node* cur = obj.root;
do {
os << cur->value << ' ';
cur = cur->right;
} while (cur != obj.root);
return os;
}
int tree::sum(node* p) {
int result = 0;
queue<node*> que;
que.push(p);
while (!que.empty()) {
node* cur = que.front();
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
result += cur->value;
que.pop();
}
return result;
}
void tree::recursiveDelete(node* p) {
if (p->l_child)
recursiveDelete(p->l_child);
if (p->r_child)
recursiveDelete(p->r_child);
delete(p);
}
void tree::delete_level(int i) {
queue<node*> que;
que.push(root);
int levelCount = 0;
while (!que.empty()) {
int size = que.size();
++levelCount;
while (size--) {
node* cur = que.front();
if (levelCount == i - 1) {
node* l = cur->l_child;
cur->l_child = l->l_child;
if (l->r_child)
recursiveDelete(l->r_child);
delete(l);
node* r = cur->r_child;
cur->r_child = r->l_child;
if (r->r_child)
recursiveDelete(r->r_child);
delete(r);
}
else {
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
}
que.pop();
}
}
node* prev = nullptr;
que.push(root);
while (!que.empty()) {
int size = que.size();
while (size--) {
node* cur = que.front();
if (prev)
prev->right = cur;
prev = cur;
if (cur->l_child)
que.push(cur->l_child);
if (cur->r_child)
que.push(cur->r_child);
que.pop();
}
}
prev->right = root;
}
node* tree::find(int i) {
node* cur = root;
while (cur->right != root)
if (cur->value == i)
return cur;
else
cur = cur->right;
return cur->value == i ? cur : nullptr;
}
Test Code
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#include <ctime>
int main() {
int m = 10;
while (m--) {
int n = 10000;
clock_t begin, end;
begin = clock();
while (n--) {
tree T1(3);
tree T2 = { 4, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 };
tree T3(T2);
tree T4;
T4 = T3;
T4 = T3.ThreeTimes();
T4.delete_level(3);
T3.sum(T3.find(12));
}
end = clock();
cout << (end - begin) / 1000.0 << endl;
}
getchar();
getchar();
return 0;
}
Benchmark, with 1000 loop and 10 tests.
Raw Pointer Version
Time / Second
Smart Pointer Version
Time / Second
