Submission #1779419

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Source Code Expand

n,s=map(int,input().split())
h=list(map(int,input().split()))
s -= 1
g=[ [] for _ in range(n) ]
for _ in range(n-1):
  a,b=map(int,input().split())
  a -= 1
  b -= 1
  g[a].append(b)
  g[b].append(a)

while True:
  change = False
  for i in range(n):
    if len(g[i]) == 1 and h[i] == 0 and i != s:
      change = True
      a = i
      b = g[i][0]
      g[a].remove(b)
      g[b].remove(a)
  if not change: break
ans = 0
for i in range(n):
  ans += len(g[i])
print(ans)

Submission Info

Judge Result