Submission #1083640

#	Time	Username	Problem	Language	Result	Execution time	Memory
1083640		LouisCheng	Senior Postmen (BOI14_postmen)	Cpython 3	0 / 100	22 ms	5980 KiB

postmen

import sys

# sys.stdin = open("1.in", "r")
sys.setrecursionlimit(int(5e5) + 1)

n, m = map(int, input().split())
paths = [set() for _ in range(n)]
for _ in range(m):
    a, b = map(lambda x: int(x) - 1, input().split())
    paths[a].add(b)
    paths[b].add(a)

res = []

def solve(node):
    while paths[node]:
        top = paths[node].pop()
        paths[top].discard(node)
        solve(top)
    res.append(node)

solve(0)

last = [len(res)] * n
next = [len(res)] * len(res)
for i in range(len(res) - 1, -1, -1):
    next[i] = last[res[i]]
    if last[res[i]] == len(res): last[res[i]] = i

nested = [[]]
ends = [len(res) - 1]
for i in range(len(res)):
    if ends[-1] == i:
        ends.pop()
        print(*nested.pop())
        continue
    nested[-1].append(res[i] + 1)
    if next[i] < ends[-1]:
        nested.append([res[i] + 1])
        ends.append(next[i])

• Subtask 1: 0 / 38
• Subtask 2: 0 / 17
• Subtask 3: 0 / 45