Leetcode 707. Design Linked List

Problem: https://leetcode.com/problems/design-linked-list/

	#include <bits/stdc++.h>
	using namespace std;
	// 構造体
	struct Node {
	int val;
	Node* next;
	Node(int x) {
	this->val = x;
	this->next = NULL;
	}
	};
	class MyLinkedList {
	public:
	// head アドレスメモ
	Node* head = new Node(0);
	int size = 0;
	MyLinkedList() {}
	int get(int index) {
	// 例外
	if (index >= size) return -1;
	// index まで進む
	auto cur = head;
	for (int i = 0; i < index; i++) {
	cur = cur->next;
	}
	return cur->val;
	}
	void addAtHead(int val) {
	// 空なら
	if (size == 0) {
	head->val = val;
	size++;
	return;
	}
	// メンバーを作成
	Node* node = new Node(val);
	size++;
	// 追加 & head 更新
	node->next = head;
	head = node;
	}
	void addAtTail(int val) {
	// 空なら
	if (size == 0) {
	head->val = val;
	size++;
	return;
	}
	// メンバーを作成
	Node* node = new Node(val);
	size++;
	// tail まで進む
	auto cur = head;
	while (cur->next) cur = cur->next;
	// list に追加
	cur->next = node;
	}
	void addAtIndex(int index, int val) {
	// 例外
	if (index > size) return;
	// tail に追加
	if (index == size) {
	addAtTail(val);
	return;
	}
	// head に追加
	if (index == 0) {
	addAtHead(val);
	return;
	}
	// メンバーを作成
	Node* node = new Node(val);
	size++;
	// index まで進む
	auto cur = head;
	for (int i = 0; i < index - 1; i++) {
	cur = cur->next;
	}
	node->next = cur->next;
	cur->next = node;
	}
	void deleteAtIndex(int index) {
	if (size < index + 1) return;
	size--;
	if (index == 0) {
	head = head->next;
	return;
	}
	// index 直前まで進む
	auto cur = head;
	for (int i = 0; i < index - 1; i++) {
	cur = cur->next;
	}
	cur->next = cur->next->next;
	}
	void print() {
	cout << "size: " << size << endl;
	if (size <= 0) return;
	auto cur = head;
	while (cur) {
	cout << cur->val << " ";
	cur = cur->next;
	}
	cout << endl;
	}
	};
	void solve() {
	MyLinkedList* obj = new MyLinkedList();
	obj->addAtHead(7);
	obj->addAtHead(2);
	obj->addAtHead(1);
	obj->addAtIndex(3, 0);
	obj->print();
	obj->deleteAtIndex(2);
	obj->print();
	}
	int main() {
	solve();
	return 0;
	}

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