下列代码实现了树的深度优先遍历,则横线处应填入( )。class TreeNode: def __init__(self, x): self.val = x self.left = None self.right = None def dfs1(root): if not root: return temp = [] temp.append(root) while temp: node = temp[-1] temp.pop() print(node.val, end=" ") if node.right: temp.append(node.right) if node.left: temp.append(node.left) def dfs2(root): if not root: return st = [] st.append(root) while st: node = st[-1] st.pop() print(node.val, end=" ") if node.right: st.append(node.right) ——————————————————
A. if node.left: st.append(node.left)Copy
B. if node.right: st.append(node.left)Copy
C. if node.left: st.append(node.right)Copy
D. if node.right: st.append(node.right)Copy
正确答案:A
试卷来源:202512 CCF-GESP编程能力等级认证Python六级真题