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Commit 9d76d65

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feat: add swift implementation to lcci problem: No.04.10 (doocs#2661)
1 parent 210021b commit 9d76d65

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3 files changed

+127
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3 files changed

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‎lcci/04.10.Check SubTree/README.md‎

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@@ -269,6 +269,49 @@ impl Solution {
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}
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```
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```swift
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/* class TreeNode {
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* var val: Int
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* var left: TreeNode?
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* var right: TreeNode?
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*
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* init(_ val: Int, _ left: TreeNode? = nil, _ right: TreeNode? = nil) {
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* self.val = val
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* self.left = left
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* self.right = right
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* }
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* }
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*/
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class Solution {
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func checkSubTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t2 == nil {
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return true
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}
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if t1 == nil {
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return false
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}
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if isSameTree(t1, t2) {
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return true
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}
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return checkSubTree(t1!.left, t2) || checkSubTree(t1!.right, t2)
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}
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private func isSameTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t1 == nil && t2 == nil {
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return true
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}
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if t1 == nil || t2 == nil {
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return false
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}
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if t1!.val != t2!.val {
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return false
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}
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return isSameTree(t1!.left, t2!.left) && isSameTree(t1!.right, t2!.right)
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}
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}
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```
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<!-- tabs:end -->
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<!-- end -->

‎lcci/04.10.Check SubTree/README_EN.md‎

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Original file line numberDiff line numberDiff line change
@@ -42,7 +42,7 @@ First, we check if $t_2$ is null. If it is, then $t_2$ is definitely a subtree o
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Otherwise, we check if $t_1$ is null. If it is, then $t_2$ is definitely not a subtree of $t_1,ドル so we return `false`.
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Next, we check if $t_1$ and $t_2$ are equal. If they are, then $t_2$ is a subtree of $t_1,ドル so we return `true`. Otherwise, we recursively check if $t_1$'s left subtree is equal to $t_2,ドル and if $t_1$'s right subtree is equal to $t_2$. If either is `true`, then $t_2$ is a subtree of $t_1`, so we return `true`.
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Next, we check if $t_1$ and $t_2$ are equal. If they are, then $t_2$ is a subtree of $t_1,ドル so we return `true`. Otherwise, we recursively check if $t_1$'s left subtree is equal to $t_2,ドル and if $t_1$'s right subtree is equal to $t_2$. If either is `true`, then $t_2$ is a subtree of $t_1$, so we return `true`.
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The time complexity is $O(n^2),ドル and the space complexity is $O(n)$. Where $n$ is the number of nodes in $t_1$.
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@@ -276,6 +276,49 @@ impl Solution {
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}
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```
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```swift
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/* class TreeNode {
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* var val: Int
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* var left: TreeNode?
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* var right: TreeNode?
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*
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* init(_ val: Int, _ left: TreeNode? = nil, _ right: TreeNode? = nil) {
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* self.val = val
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* self.left = left
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* self.right = right
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* }
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* }
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*/
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class Solution {
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func checkSubTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t2 == nil {
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return true
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}
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if t1 == nil {
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return false
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}
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if isSameTree(t1, t2) {
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return true
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}
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return checkSubTree(t1!.left, t2) || checkSubTree(t1!.right, t2)
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}
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private func isSameTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t1 == nil && t2 == nil {
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return true
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}
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if t1 == nil || t2 == nil {
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return false
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}
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if t1!.val != t2!.val {
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return false
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}
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return isSameTree(t1!.left, t2!.left) && isSameTree(t1!.right, t2!.right)
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}
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}
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```
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<!-- tabs:end -->
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<!-- end -->
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,40 @@
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/* class TreeNode {
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* var val: Int
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* var left: TreeNode?
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* var right: TreeNode?
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*
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* init(_ val: Int, _ left: TreeNode? = nil, _ right: TreeNode? = nil) {
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* self.val = val
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* self.left = left
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* self.right = right
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* }
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* }
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*/
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class Solution {
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func checkSubTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t2 == nil {
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return true
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}
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if t1 == nil {
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return false
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}
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if isSameTree(t1, t2) {
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return true
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}
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return checkSubTree(t1!.left, t2) || checkSubTree(t1!.right, t2)
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}
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private func isSameTree(_ t1: TreeNode?, _ t2: TreeNode?) -> Bool {
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if t1 == nil && t2 == nil {
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return true
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}
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if t1 == nil || t2 == nil {
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return false
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}
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if t1!.val != t2!.val {
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return false
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}
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return isSameTree(t1!.left, t2!.left) && isSameTree(t1!.right, t2!.right)
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}
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}

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