CCC 2018 J5: Choose your own path

This is graph question, use DFS to do it.

1. Start from the first page, use DFS to iterative all neighbor pages.

Update the minimum distance of each page to the first page.

2. Check if all pages are visited, print results.

This is the python solution:

N = int(input())
book = []
book.append([])
visited = []
visited.append(1)
minPath = N+1
dist = [minPath]

for i in range(N):
    pp = input().split()
    if int(pp[0]) == 0:
        visited.append(0)
        book.append([0])
        dist.append(minPath)
        continue
    curlist = []
    for j in range(1, len(pp), 1):
        curlist.append(int(pp[j]))
    book.append(curlist)
    visited.append(0)
    dist.append(minPath)

stacklist = [1]
visited[1] = 1
dist[1] = 1

while len(stacklist) > 0:
    n = stacklist.pop()
    p = dist[n]
    for x in book[n]:
        if x == 0:
            if minPath > p:
                minPath = p
        else:
            if p+1 < dist[x]:
                dist[x] = p+1
                visited[x] = 0
            if visited[x] == 0:
                stacklist.append(x)
                visited[x] = 1

allvisited = True
for x in visited:
    if x == 0:
        allvisited = False
        break

if allvisited:
    print("Y")
else:
    print("N")
print(minPath)