181 lines
3.6 KiB
C++
181 lines
3.6 KiB
C++
#include <iostream>
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#include <memory>
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#include <utility>
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class Node {
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public:
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Node(const int value, std::unique_ptr<Node> next)
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: next_(std::move(next)), value_(value) {}
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explicit Node(const int v)
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: Node(v, nullptr) {}
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const Node* next() const { return next_.get(); }
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Node* next() { return next_.get(); }
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int value() const { return value_; }
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void setNext(std::unique_ptr<Node> next) { next_ = std::move(next); }
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std::unique_ptr<Node> getNext() { return std::move(next_); }
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private:
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std::unique_ptr<Node> next_;
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int value_;
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};
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// ht
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// 1
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// h t
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// 2 -> 1
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// h t
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// 3 -> 2 -> 1
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// h t
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// 4 -> 3 -> 2 -> 1
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// h t
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// 4 -> 3 -> 2 -> 1 -> 5
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//
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// 3 -> 2 -> 1 -> 5
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// 3 -> 1 -> 5
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class List {
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public:
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void pushFront(int value) {
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if (!head_) {
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pushHead(value);
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return;
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}
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head_ = std::make_unique<Node>(value, std::move(head_));
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}
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void pushBack(int value) {
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if (!tail_) {
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pushHead(value);
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return;
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}
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tail_->setNext(std::make_unique<Node>(value));
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tail_ = tail_->next();
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}
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bool erase(int value) {
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// Remove head
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if (head_ && head_->value() == value) {
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head_ = head_->getNext();
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if (!head_) {
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tail_ = nullptr;
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}
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return true;
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}
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if (auto* node = findPrevNode(value)) {
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// Remove tail
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if (node->next() == tail_) {
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tail_ = node;
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}
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node->setNext(std::move(node->next()->getNext()));
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return true;
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}
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return false;
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}
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const Node* findByValue(const int value) const {
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const auto* current = head_.get();
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while (current) {
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if (current->value() == value) {
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return current;
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}
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current = current->next();
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}
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return nullptr;
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}
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void print() const {
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const auto* current = head_.get();
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while (current) {
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std::cout << current->value() << ' ';
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current = current->next();
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}
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std::cout << '\n';
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}
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private:
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// ht
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// 1
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// h t
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// 2 -> 1
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// h t
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// 2 -> 1 -> 3
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// 2 -> 3
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void pushHead(int value) {
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head_ = std::make_unique<Node>(value);
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tail_ = head_.get();
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}
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Node* findPrevNode(const int value) const {
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auto* current = head_.get();
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Node* prev = nullptr;
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while (current) {
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if (current->value() == value) {
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return prev;
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}
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prev = current;
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current = current->next();
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}
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return nullptr;
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}
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std::unique_ptr<Node> head_;
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Node* tail_{nullptr};
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};
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int main() {
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List list;
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list.pushFront(4);
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list.pushFront(2);
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list.pushFront(7);
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list.pushFront(9);
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list.print();
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if (const auto* const node = list.findByValue(1)) {
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std::cout << node->value() << '\n';
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} else {
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std::cout << "can't find node with value 1\n";
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}
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if (const auto* const node = list.findByValue(7)) {
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std::cout << node->value() << '\n';
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} else {
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std::cout << "can't find node with value 7\n";
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}
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list.pushBack(10);
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list.print();
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list.pushBack(12);
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list.pushFront(3);
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list.pushFront(5);
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list.pushBack(13);
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list.print();
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list.erase(2);
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list.print();
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list.erase(5);
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list.print();
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list.erase(13);
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list.print();
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list.erase(12);
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list.print();
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list.pushBack(40);
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list.print();
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return 0;
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}
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