[Algorithms] Double Linked List 구현

/// === main.cpp ===
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

const int MAX_LEN = 1100000;
int N, bn;
struct Node {
	char val;
	Node* prev;
	Node* next;
	Node() : prev(NULL), next(NULL), val(0) {}

	Node* alloc(char _val, Node *_prev, Node *_next){
		val = _val;
		prev = _prev;
		next = _next;

		return this;
	}
}buf[MAX_LEN];

Node* Head;
Node* cursor;

void insert(char ch){
	Node* temp = buf[bn++].alloc(ch, NULL, NULL);
	temp->val = ch;
	temp->next = cursor->next;
	temp->prev = cursor;

	if (cursor->next != NULL) cursor->next->prev = temp;
	cursor->next = temp;
	cursor = temp;
}

void leftMove(){
	if (cursor->prev != NULL){
		cursor = cursor->prev;
	}
}
void rightMove(){
	if (cursor->next != NULL){
		cursor = cursor->next;
	}
}
void remove(){
	if (cursor->prev != NULL){
		cursor->prev->next = cursor->next;
		if (cursor->next != NULL) cursor->next->prev = cursor->prev;
		cursor = cursor->prev;
	}
}
char arr[MAX_LEN];
int main(){
	//freopen("input.txt", "r", stdin);
	scanf("%d", &N);
	char t;
	for (int T = 0; T < N; T++){
		bn = 0;
		cursor = buf[bn++].alloc(0, NULL, NULL);
		Head = cursor;
		for (int i = 0; i < MAX_LEN; i++) arr[i] = 0;
		scanf("%s", &arr);

		for (int i = 0; t = arr[i]; i++){
			
			if (t == '<'){
				leftMove();
			}
			else if (t == '>'){
				rightMove();
			}
			else if (t == '-'){
				remove();
			}
			else {
				insert(t);
			}
		}
		while (Head->next != NULL){
			printf("%c", Head->next->val);
			Head = Head->next;
		}
		printf("\n");
	}
	return 0;
}