[트리] 트리 순회 (백준 1991번)

정은경·2020년 3월 22일

백준 문제풀이

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문제

나의 풀이

import sys

N = int(input())

class Node:
    def __init__(self, data, L, R):
        self.data = data
        self.l = L
        self.r = R

def preorder(node):
    print(node.data, end='')
    if node.l != '.':
        preorder(tree[node.l])
    if node.r != '.':
        preorder(tree[node.r])

def inorder(node):
    if node.l != '.':
        inorder(tree[node.l])
    print(node.data, end='')
    if node.r != '.':
        inorder(tree[node.r])

def postorder(node):
    if node.l != '.':
        postorder(tree[node.l])
    if node.r != '.':
        postorder(tree[node.r])
    print(node.data, end='')

tree = {}
for i in range(N):
    node, L, R = input().split()
    tree[node] = Node(node,L,R)

preorder(tree['A'])
print()
inorder(tree['A'])
print()
postorder(tree['A'])
print()

남의 풀이

import sys
sys.setrecursionlimit(1000000)
 
n = int(sys.stdin.readline())
tree = dict()
root = 'A'
 
class node:
    def __init__(self):
        self.data = None
        self.left = None
        self.right = None
 
def preorder(node):
    sys.stdout.write(node.data)
    if node.left is not None:
        preorder(tree[node.left])
    if node.right is not None:
        preorder(tree[node.right])
 
def inorder(node):
    if node.left is not None:
        inorder(tree[node.left])
    sys.stdout.write(node.data)
    if node.right is not None:
        inorder(tree[node.right])
 
def postorder(node):
    if node.left is not None:
        postorder(tree[node.left])
    if node.right is not None:
        postorder(tree[node.right])
    sys.stdout.write(node.data)
 
 
for i in range(n):
    a, b, c = sys.stdin.readline().split()
    if a == root:
        tree[root] = node()
        tree[root].data = a
        if b != '.':
            tree[root].left = b
            tree[b] = node()
            tree[b].data = b
        if c!= '.':
            tree[root].right = c
            tree[c] = node()
            tree[c].data = c
    else:
        if b!= '.':
            tree[a].left = b
            tree[b] = node()
            tree[b].data = b
        if c!= '.':
            tree[a].right = c
            tree[c] = node()
            tree[c].data = c
 
preorder(tree[root])
sys.stdout.write('\n')
inorder(tree[root])
sys.stdout.write('\n')
postorder(tree[root])