Commit 72536f4

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feat: add swift implementation to lcci problem: No.04.04 (doocs#2653)

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Lines changed: 34 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -167,6 +167,40 @@ function isBalanced(root: TreeNode \| null): boolean {`
`167`	`167`	`}`
`168`	`168`	```
`169`	`169`
	`170`	+```swift
	`171`	`+/* class TreeNode {`
	`172`	`+* var val: Int`
	`173`	`+* var left: TreeNode?`
	`174`	`+* var right: TreeNode?`
	`175`	`+*`
	`176`	`+* init(_ val: Int) {`
	`177`	`+* self.val = val`
	`178`	`+* self.left = nil`
	`179`	`+* self.right = nil`
	`180`	`+* }`
	`181`	`+* }`
	`182`	`+*/`
	`183`	`+`
	`184`	`+class Solution {`
	`185`	`+ func isBalanced(_ root: TreeNode?) -> Bool {`
	`186`	`+ return dfs(root) >= 0`
	`187`	`+ }`
	`188`	`+`
	`189`	`+ private func dfs(_ root: TreeNode?) -> Int {`
	`190`	`+ guard let root = root else {`
	`191`	`+ return 0`
	`192`	`+ }`
	`193`	`+`
	`194`	`+ let leftHeight = dfs(root.left)`
	`195`	`+ let rightHeight = dfs(root.right)`
	`196`	`+ if leftHeight < 0 \|\| rightHeight < 0 \|\| abs(leftHeight - rightHeight) > 1 {`
	`197`	`+ return -1`
	`198`	`+ }`
	`199`	`+ return max(leftHeight, rightHeight) + 1`
	`200`	`+ }`
	`201`	`+}`
	`202`	+```
	`203`	`+`
`170`	`204`	`<!-- tabs:end -->`
`171`	`205`
`172`	`206`	`<!-- end -->`

Lines changed: 34 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -210,6 +210,40 @@ function isBalanced(root: TreeNode \| null): boolean {`
`210`	`210`	`}`
`211`	`211`	```
`212`	`212`
	`213`	+```swift
	`214`	`+/* class TreeNode {`
	`215`	`+* var val: Int`
	`216`	`+* var left: TreeNode?`
	`217`	`+* var right: TreeNode?`
	`218`	`+*`
	`219`	`+* init(_ val: Int) {`
	`220`	`+* self.val = val`
	`221`	`+* self.left = nil`
	`222`	`+* self.right = nil`
	`223`	`+* }`
	`224`	`+* }`
	`225`	`+*/`
	`226`	`+`
	`227`	`+class Solution {`
	`228`	`+ func isBalanced(_ root: TreeNode?) -> Bool {`
	`229`	`+ return dfs(root) >= 0`
	`230`	`+ }`
	`231`	`+`
	`232`	`+ private func dfs(_ root: TreeNode?) -> Int {`
	`233`	`+ guard let root = root else {`
	`234`	`+ return 0`
	`235`	`+ }`
	`236`	`+`
	`237`	`+ let leftHeight = dfs(root.left)`
	`238`	`+ let rightHeight = dfs(root.right)`
	`239`	`+ if leftHeight < 0 \|\| rightHeight < 0 \|\| abs(leftHeight - rightHeight) > 1 {`
	`240`	`+ return -1`
	`241`	`+ }`
	`242`	`+ return max(leftHeight, rightHeight) + 1`
	`243`	`+ }`
	`244`	`+}`
	`245`	+```
	`246`	`+`
`213`	`247`	`<!-- tabs:end -->`
`214`	`248`
`215`	`249`	`<!-- end -->`

Lines changed: 31 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,31 @@`
	`1`	`+/* class TreeNode {`
	`2`	`+* var val: Int`
	`3`	`+* var left: TreeNode?`
	`4`	`+* var right: TreeNode?`
	`5`	`+*`
	`6`	`+* init(_ val: Int) {`
	`7`	`+* self.val = val`
	`8`	`+* self.left = nil`
	`9`	`+* self.right = nil`
	`10`	`+* }`
	`11`	`+* }`
	`12`	`+*/`
	`13`	`+`
	`14`	`+class Solution {`
	`15`	`+ func isBalanced(_ root: TreeNode?) -> Bool {`
	`16`	`+ return dfs(root) >= 0`
	`17`	`+ }`
	`18`	`+`
	`19`	`+ private func dfs(_ root: TreeNode?) -> Int {`
	`20`	`+ guard let root = root else {`
	`21`	`+ return 0`
	`22`	`+ }`
	`23`	`+`
	`24`	`+ let leftHeight = dfs(root.left)`
	`25`	`+ let rightHeight = dfs(root.right)`
	`26`	`+ if leftHeight < 0 \|\| rightHeight < 0 \|\| abs(leftHeight - rightHeight) > 1 {`
	`27`	`+ return -1`
	`28`	`+ }`
	`29`	`+ return max(leftHeight, rightHeight) + 1`
	`30`	`+ }`
	`31`	`+}`

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