|
| 1 | +from typing import Optional |
| 2 | +from unittest import TestCase, main |
| 3 | + |
| 4 | + |
| 5 | +# Definition for a binary tree node. |
| 6 | +class TreeNode: |
| 7 | + def __init__(self, val=0, left=None, right=None): |
| 8 | + self.val = val |
| 9 | + self.left = left |
| 10 | + self.right = right |
| 11 | + |
| 12 | + |
| 13 | +class Solution: |
| 14 | + def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool: |
| 15 | + return self.solve_dfs(p, q) |
| 16 | + |
| 17 | + """ |
| 18 | + Runtime: 0 ms (Beats 100.00%) |
| 19 | + Time Complexity: O(min(p, q)) |
| 20 | + > dfs를 통해 모든 node를 방문하므로, 각 트리의 node의 갯수를 각각 p, q라 하면, O(min(p, q)) |
| 21 | +
|
| 22 | + Memory: 16.62 MB (Beats 15.78%) |
| 23 | + Space Complexity: O(min(p, q)) |
| 24 | + > 일반적인 경우 트리의 깊이만큼 dfs 호출 스택이 쌓이나, 최악의 경우 한쪽으로 편향되었다면 O(min(p, q)), upper bound |
| 25 | + """ |
| 26 | + def solve_dfs(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool: |
| 27 | + |
| 28 | + def dfs(p: Optional[TreeNode], q: Optional[TreeNode]) -> bool: |
| 29 | + if p is None and q is None: |
| 30 | + return True |
| 31 | + elif (p is not None and q is not None) and (p.val == q.val): |
| 32 | + return dfs(p.left, q.left) and dfs(p.right, q.right) |
| 33 | + else: |
| 34 | + return False |
| 35 | + |
| 36 | + return dfs(p, q) |
| 37 | + |
| 38 | + |
| 39 | +class _LeetCodeTestCases(TestCase): |
| 40 | + def test_1(self): |
| 41 | + p_1 = TreeNode(1) |
| 42 | + p_2 = TreeNode(2) |
| 43 | + p_3 = TreeNode(3) |
| 44 | + p_1.left = p_2 |
| 45 | + p_1.right = p_3 |
| 46 | + |
| 47 | + q_1 = TreeNode(1) |
| 48 | + q_2 = TreeNode(3) |
| 49 | + q_3 = TreeNode(3) |
| 50 | + q_1.left = q_2 |
| 51 | + q_1.right = q_3 |
| 52 | + |
| 53 | + self.assertEqual(Solution().isSameTree(p_1, q_1), True) |
| 54 | + |
| 55 | + |
| 56 | +if __name__ == '__main__': |
| 57 | + main() |
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