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merged 2 commits into from
Aug 4, 2024
Merged

feat: update lc problems #3360

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feat: update lc problems
yanglbme Aug 4, 2024
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idoocs Aug 4, 2024
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2 changes: 1 addition & 1 deletion solution/0100-0199/0191.Number of 1 Bits/README_EN.md
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ tags:
<p><strong>Constraints:</strong></p>

<ul>
<li><code>1 &lt;= n&nbsp;&lt;= 2<sup>31</sup>&nbsp;- 1</code></li>
<li><code>1 &lt;= n &lt;= 2<sup>31</sup> - 1</code></li>
</ul>

<p>&nbsp;</p>
Expand Down
162 changes: 74 additions & 88 deletions solution/0500-0599/0572.Subtree of Another Tree/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,13 @@ tags:

<!-- solution:start -->

### 方法一
### 方法一：DFS

我们定义一个辅助函数 $\textit{same}(p, q)$，用于判断以 $p$ 为根节点的树和以 $q$ 为根节点的树是否相等。如果两棵树的根节点的值相等，并且它们的左子树和右子树也分别相等，那么这两棵树是相等的。

在 $\textit{isSubtree}(\textit{root}, \textit{subRoot})$ 函数中，我们首先判断 $\textit{root}$ 是否为空，如果为空，则返回 $\text{false}$。否则，我们判断 $\textit{root}$ 和 $\textit{subRoot}$ 是否相等，如果相等，则返回 $\text{true}$。否则，我们递归地判断 $\textit{root}$ 的左子树和右子树是否包含 $\textit{subRoot}$。

时间复杂度 $O(n \times m)$，空间复杂度 $O(n)$。其中 $n$ 和 $m$ 分别是树 $root$ 和树 $subRoot$ 的节点个数。

<!-- tabs:start -->

Expand All @@ -75,22 +81,16 @@ tags:
# self.left = left
# self.right = right
class Solution:
def isSubtree(self, root: TreeNode, subRoot: TreeNode) -> bool:
def dfs(root1, root2):
if root1 is None and root2 is None:
return True
if root1 is None or root2 is None:
return False
return (
root1.val == root2.val
and dfs(root1.left, root2.left)
and dfs(root1.right, root2.right)
)
def isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:
def same(p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
if p is None or q is None:
return p is q
return p.val == q.val and same(p.left, q.left) and same(p.right, q.right)

if root is None:
return False
return (
dfs(root, subRoot)
same(root, subRoot)
or self.isSubtree(root.left, subRoot)
or self.isSubtree(root.right, subRoot)
)
Expand Down Expand Up @@ -119,19 +119,15 @@ class Solution {
if (root == null) {
return false;
}
return dfs(root, subRoot) || isSubtree(root.left, subRoot)
return same(root, subRoot) || isSubtree(root.left, subRoot)
|| isSubtree(root.right, subRoot);
}

private boolean dfs(TreeNode root1, TreeNode root2) {
if (root1 == null && root2 == null) {
return true;
}
if (root1 == null || root2 == null) {
return false;
private boolean same(TreeNode p, TreeNode q) {
if (p == null || q == null) {
return p == q;
}
return root1.val == root2.val && dfs(root1.left, root2.left)
&& dfs(root1.right, root2.right);
return p.val == q.val && same(p.left, q.left) && same(p.right, q.right);
}
}
```
Expand All @@ -153,14 +149,17 @@ class Solution {
class Solution {
public:
bool isSubtree(TreeNode* root, TreeNode* subRoot) {
if (!root) return 0;
return dfs(root, subRoot) || isSubtree(root->left, subRoot) || isSubtree(root->right, subRoot);
if (!root) {
return false;
}
return same(root, subRoot) || isSubtree(root->left, subRoot) || isSubtree(root->right, subRoot);
}

bool dfs(TreeNode* root1, TreeNode* root2) {
if (!root1 && !root2) return 1;
if (!root1 || !root2) return 0;
return root1->val == root2->val && dfs(root1->left, root2->left) && dfs(root1->right, root2->right);
bool same(TreeNode* p, TreeNode* q) {
if (!p || !q) {
return p == q;
}
return p->val == q->val && same(p->left, q->left) && same(p->right, q->right);
}
};
```
Expand All @@ -177,20 +176,17 @@ public:
* }
*/
func isSubtree(root *TreeNode, subRoot *TreeNode) bool {
var same func(p, q *TreeNode) bool
same = func(p, q *TreeNode) bool {
if p == nil || q == nil {
return p == q
}
return p.Val == q.Val && same(p.Left, q.Left) && same(p.Right, q.Right)
}
if root == nil {
return false
}
var dfs func(root1, root2 *TreeNode) bool
dfs = func(root1, root2 *TreeNode) bool {
if root1 == nil && root2 == nil {
return true
}
if root1 == nil || root2 == nil {
return false
}
return root1.Val == root2.Val && dfs(root1.Left, root2.Left) && dfs(root1.Right, root2.Right)
}
return dfs(root, subRoot) || isSubtree(root.Left, subRoot) || isSubtree(root.Right, subRoot)
return same(root, subRoot) || isSubtree(root.Left, subRoot) || isSubtree(root.Right, subRoot)
}
```

Expand All @@ -210,22 +206,17 @@ func isSubtree(root *TreeNode, subRoot *TreeNode) bool {
* }
* }
*/

const dfs = (root: TreeNode | null, subRoot: TreeNode | null) => {
if (root == null && subRoot == null) {
return true;
}
if (root == null || subRoot == null || root.val !== subRoot.val) {
return false;
}
return dfs(root.left, subRoot.left) && dfs(root.right, subRoot.right);
};

function isSubtree(root: TreeNode | null, subRoot: TreeNode | null): boolean {
if (root == null) {
const same = (p: TreeNode | null, q: TreeNode | null): boolean => {
if (!p || !q) {
return p === q;
}
return p.val === q.val && same(p.left, q.left) && same(p.right, q.right);
};
if (!root) {
return false;
}
return dfs(root, subRoot) || isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
return same(root, subRoot) || isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
}
```

Expand All @@ -252,38 +243,36 @@ function isSubtree(root: TreeNode | null, subRoot: TreeNode | null): boolean {
// }
use std::cell::RefCell;
use std::rc::Rc;
impl Solution {
fn dfs(root: &Option<Rc<RefCell<TreeNode>>>, sub_root: &Option<Rc<RefCell<TreeNode>>>) -> bool {
if root.is_none() && sub_root.is_none() {
return true;
}
if root.is_none() || sub_root.is_none() {
return false;
}
let root = root.as_ref().unwrap().borrow();
let sub_root = sub_root.as_ref().unwrap().borrow();
root.val == sub_root.val
&& Self::dfs(&root.left, &sub_root.left)
&& Self::dfs(&root.right, &sub_root.right)
}

fn help(
root: &Option<Rc<RefCell<TreeNode>>>,
sub_root: &Option<Rc<RefCell<TreeNode>>>,
impl Solution {
pub fn is_subtree(
root: Option<Rc<RefCell<TreeNode>>>,
sub_root: Option<Rc<RefCell<TreeNode>>>,
) -> bool {
if root.is_none() {
return false;
}
Self::dfs(root, sub_root)
|| Self::help(&root.as_ref().unwrap().borrow().left, sub_root)
|| Self::help(&root.as_ref().unwrap().borrow().right, sub_root)
Self::same(&root, &sub_root)
|| Self::is_subtree(
root.as_ref().unwrap().borrow().left.clone(),
sub_root.clone(),
)
|| Self::is_subtree(
root.as_ref().unwrap().borrow().right.clone(),
sub_root.clone(),
)
}

pub fn is_subtree(
root: Option<Rc<RefCell<TreeNode>>>,
sub_root: Option<Rc<RefCell<TreeNode>>>,
) -> bool {
Self::help(&root, &sub_root)
fn same(p: &Option<Rc<RefCell<TreeNode>>>, q: &Option<Rc<RefCell<TreeNode>>>) -> bool {
match (p, q) {
(None, None) => true,
(Some(p), Some(q)) => {
let p = p.borrow();
let q = q.borrow();
p.val == q.val && Self::same(&p.left, &q.left) && Self::same(&p.right, &q.right)
}
_ => false,
}
}
}
```
Expand All @@ -305,19 +294,16 @@ impl Solution {
* @return {boolean}
*/
var isSubtree = function (root, subRoot) {
if (!root) return false;
let dfs = function (root1, root2) {
if (!root1 && !root2) {
return true;
const same = (p, q) => {
if (!p || !q) {
return p === q;
}
if (!root1 || !root2) {
return false;
}
return (
root1.val == root2.val && dfs(root1.left, root2.left) && dfs(root1.right, root2.right)
);
return p.val === q.val && same(p.left, q.left) && same(p.right, q.right);
};
return dfs(root, subRoot) || isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
if (!root) {
return false;
}
return same(root, subRoot) || isSubtree(root.left, subRoot) || isSubtree(root.right, subRoot);
};
```

Expand Down
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