Astralis session I

from collections import deque

n = int(input())
componentSize = n // 2

# print("componentSize:", componentSize)

solarConnectionsList = [[] for i in range(n)]
solarAllocation = ["" for i in range(n)]

for i in range(n - 1):
  solar1, solar2 = map(int, input().split())
  solarConnectionsList[solar1 - 1].append(solar2 - 1)
  solarConnectionsList[solar2 - 1].append(solar1 - 1)

# print("solarConnectionsList:", solarConnectionsList)

visited = set()
componentCount = 0

def bfs(i):
  global componentCount
  global solarAllocation
  global visited

  q = deque([i])
  count = 0
  componentCount += 1
  
  while q:
    # means reach the size of what a component should be, then stop
    if count == componentSize:
      # componentCount += 1
      break

    node = q.popleft()
    # print("in queue, popped node:", node)
    # mark node as visited
    visited.add(node)
    # mark who gets this node, Uolevi or Maija
    # print("HERE, compoentcount:", componentCount)

    if componentCount == 1:
      solarAllocation[node] = "U"
    else:
      solarAllocation[node] = "M"

    # print("SOLARALLOCATION:", solarAllocation)
    # print("solarConnectionsList[node]:", solarConnectionsList[node])
    # increment count
    count += 1
    # get neighbours of node and add to queue
    for neighbour in solarConnectionsList[node]:
      if neighbour not in visited:
        q.append(neighbour)

flag = True

for i in range(n):
  # print("i:", i)
  # print("visited:", visited)

  if i not in visited:
    # print("Not in visited, node:", i)
    # if bfs for 2 components already that means no solution
    # print("componentcount:", componentCount)
    if componentCount == 2:
      flag = False
    else:
      bfs(i)
      # print("node:", i)

# print("solarAllocation:", solarAllocation)

if flag:
  print("Yes")
  for allocation in solarAllocation:
    print(allocation, end="")
  print()
else:
  print("No")

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: ACCEPTED

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: ACCEPTED

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: WRONG ANSWER

Test 23

Verdict: ACCEPTED

Test 24

Verdict: WRONG ANSWER

Test 25

Verdict: WRONG ANSWER

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: WRONG ANSWER

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: WRONG ANSWER

Test 33

Verdict: ACCEPTED

Test 34

Verdict: WRONG ANSWER

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: WRONG ANSWER

Test 38

Verdict: WRONG ANSWER

Test 39

Verdict: WRONG ANSWER

Test 40

Verdict: ACCEPTED

Test 41

Verdict: WRONG ANSWER

Test 42

Verdict: WRONG ANSWER

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

Test 46

Verdict: WRONG ANSWER

Test 47

Verdict: WRONG ANSWER

Test 48

Verdict: ACCEPTED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: WRONG ANSWER

Test 51

Verdict: WRONG ANSWER

Test 52

Verdict: ACCEPTED

Test 53

Verdict: WRONG ANSWER

Test 54

Verdict: WRONG ANSWER

Test 55

Verdict: WRONG ANSWER

Test 56

Verdict: WRONG ANSWER

Test 57

Verdict: WRONG ANSWER

Test 58

Verdict: WRONG ANSWER

Test 59

Verdict: WRONG ANSWER

Test 60

Verdict: WRONG ANSWER

Test 61

Verdict: ACCEPTED