백준 1991번 파이썬 (트리)
n=int(input()) t={} for i in range(n): a,b,c=map(str,input().split()) t[a]=[b,c] #left, right 자식 def preorder(root): if root!=".": print(root,end="") preorder(t[root][0]) preorder(t[root][1]) def inorder(root): if root!=".": inorder(t[root][0]) print(root,end="") inorder(t[root][1]) def postorder(root): if root!=".": postorder(t[root][0]) postorder(t[root][1]) print(root,end="") preorder('A') pr..