코드트리 - 불안한 무빙워크 (Python)

import sys
from collections import deque

# 제출 전 삭제
sys.stdin = open("input.txt")

# Solution
# Step 1: 무빙워크 1칸 회전
def rotate():
    x = front_dq.pop()
    y = back_dq.popleft()

    front_dq.appendleft(y)
    back_dq.append(x)

    if front_dq[n - 1][1] == 1:
        front_dq[n - 1][1] = 0

# Step 2: 사람 1칸씩 이동
def move():
    for i in range(n - 1, -1, -1):
        if front_dq[i][1] == 1:
            if front_dq[i + 1][0] > 0 and front_dq[i + 1][1] == 0:
                front_dq[i][1] = 0
                front_dq[i + 1][0] -= 1

                if i + 1 != n - 1:
                    front_dq[i + 1][1] = 1

                if front_dq[i + 1][0] == 0:
                    global cnt
                    cnt += 1

# Step 3: 사람 1명 추가
def add():
    if front_dq[0][0] > 0:
        front_dq[0][0] -= 1
        front_dq[0][1] = 1
        if front_dq[0][0] == 0:
            global cnt
            cnt += 1

# Main
n, k = map(int, sys.stdin.readline().split())
safe_list = list(map(int, sys.stdin.readline().split()))

front_dq = deque()
back_dq = deque()

for i in range(2 * n):
    if i < n:
        front_dq.append([safe_list[i], 0])
    else:
        back_dq.appendleft([safe_list[i], 0])

idx = 0
cnt = 0
while cnt < k:
    rotate()
    move()
    add()
    idx += 1

print(idx)