[백준] 뱀

https://www.acmicpc.net/problem/3190

import sys
input = sys.stdin.readline

N, K, board, snake, L, curve, cur_direct = [None] * 7

direct_move = {'L': (0, -1), 'R': (0, 1), 'U': (-1, 0), 'D': (1, 0)}
change_dir = {'L': {'L': 'D', 'R': 'U', 'U': 'L', 'D': 'R'}, 'D': {'L': 'U', 'R': 'D', 'U': 'R', 'D': 'L'}}


def init():
    global N, K, board, snake, L, curve, cur_direct
    N = int(input())
    K = int(input())

    board = [[-1] + [0] * N + [-1] for _ in range(N + 2)]
    board[0] = board[-1] = [-1] * (N + 2)
    board[1][1] = 1

    for i in range(K):
        row, col = list(map(lambda x: int(x), input().split(' ')))
        board[row][col] = 2  # apple

    snake = [(1, 1)]
    cur_direct = 'R'
    L = int(input())
    curve = []

    for i in range(L):
        X, C = input()[:-1].split(' ')
        curve.append((int(X), C))


def move():
    global cur_direct

    move_dist = direct_move[cur_direct]
    next_head = (snake[0][0] + move_dist[0], snake[0][1] + move_dist[1])
    if board[next_head[0]][next_head[1]] == 1 or board[next_head[0]][next_head[1]] == -1:
        return False

    if board[next_head[0]][next_head[1]] == 0:  # not apple
        tail = snake.pop()
        board[tail[0]][tail[1]] = 0

    snake.insert(0, next_head)
    board[next_head[0]][next_head[1]] = 1

    return True


def solution():
    global cur_direct

    time = 0
    while True:
        if curve:
            X, C = curve.pop(0)
            while X > time:
                time += 1
                if not move():
                    print(time)
                    return
            cur_direct = change_dir[C][cur_direct]
            time += 1
            if not move():
                print(time)
                return
        else:
            time += 1
            if not move():
                print(time)
                return


init()
solution()