Commit a3bb154

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feat: add swift implementation to lcci problem: No.17.06 (doocs#2774)

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Lines changed: 39 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -193,6 +193,45 @@ func numberOf2sInRange(n int) int {`
`193`	`193`	`}`
`194`	`194`	```
`195`	`195`
	`196`	+```swift
	`197`	`+class Solution {`
	`198`	`+ private var a = [Int](repeating: 0, count: 12)`
	`199`	`+ private var dp = [[Int]](repeating: [Int](repeating: -1, count: 12), count: 12)`
	`200`	`+`
	`201`	`+ func numberOf2sInRange(_ n: Int) -> Int {`
	`202`	`+ var n = n`
	`203`	`+ var len = 0`
	`204`	`+ while n > 0 {`
	`205`	`+ len += 1`
	`206`	`+ a[len] = n % 10`
	`207`	`+ n /= 10`
	`208`	`+ }`
	`209`	`+ for i in 0..<12 {`
	`210`	`+ dp[i] = [Int](repeating: -1, count: 12)`
	`211`	`+ }`
	`212`	`+ return dfs(len, 0, true)`
	`213`	`+ }`
	`214`	`+`
	`215`	`+ private func dfs(_ pos: Int, _ cnt: Int, _ limit: Bool) -> Int {`
	`216`	`+ if pos <= 0 {`
	`217`	`+ return cnt`
	`218`	`+ }`
	`219`	`+ if !limit && dp[pos][cnt] != -1 {`
	`220`	`+ return dp[pos][cnt]`
	`221`	`+ }`
	`222`	`+ let up = limit ? a[pos] : 9`
	`223`	`+ var ans = 0`
	`224`	`+ for i in 0...up {`
	`225`	`+ ans += dfs(pos - 1, cnt + (i == 2 ? 1 : 0), limit && i == up)`
	`226`	`+ }`
	`227`	`+ if !limit {`
	`228`	`+ dp[pos][cnt] = ans`
	`229`	`+ }`
	`230`	`+ return ans`
	`231`	`+ }`
	`232`	`+}`
	`233`	+```
	`234`	`+`
`196`	`235`	`<!-- tabs:end -->`
`197`	`236`
`198`	`237`	`<!-- end -->`

Lines changed: 39 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -196,6 +196,45 @@ func numberOf2sInRange(n int) int {`
`196`	`196`	`}`
`197`	`197`	```
`198`	`198`
	`199`	+```swift
	`200`	`+class Solution {`
	`201`	`+ private var a = [Int](repeating: 0, count: 12)`
	`202`	`+ private var dp = [[Int]](repeating: [Int](repeating: -1, count: 12), count: 12)`
	`203`	`+`
	`204`	`+ func numberOf2sInRange(_ n: Int) -> Int {`
	`205`	`+ var n = n`
	`206`	`+ var len = 0`
	`207`	`+ while n > 0 {`
	`208`	`+ len += 1`
	`209`	`+ a[len] = n % 10`
	`210`	`+ n /= 10`
	`211`	`+ }`
	`212`	`+ for i in 0..<12 {`
	`213`	`+ dp[i] = [Int](repeating: -1, count: 12)`
	`214`	`+ }`
	`215`	`+ return dfs(len, 0, true)`
	`216`	`+ }`
	`217`	`+`
	`218`	`+ private func dfs(_ pos: Int, _ cnt: Int, _ limit: Bool) -> Int {`
	`219`	`+ if pos <= 0 {`
	`220`	`+ return cnt`
	`221`	`+ }`
	`222`	`+ if !limit && dp[pos][cnt] != -1 {`
	`223`	`+ return dp[pos][cnt]`
	`224`	`+ }`
	`225`	`+ let up = limit ? a[pos] : 9`
	`226`	`+ var ans = 0`
	`227`	`+ for i in 0...up {`
	`228`	`+ ans += dfs(pos - 1, cnt + (i == 2 ? 1 : 0), limit && i == up)`
	`229`	`+ }`
	`230`	`+ if !limit {`
	`231`	`+ dp[pos][cnt] = ans`
	`232`	`+ }`
	`233`	`+ return ans`
	`234`	`+ }`
	`235`	`+}`
	`236`	+```
	`237`	`+`
`199`	`238`	`<!-- tabs:end -->`
`200`	`239`
`201`	`240`	`<!-- end -->`

Lines changed: 36 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,36 @@`
	`1`	`+class Solution {`
	`2`	`+ private var a = [Int](repeating: 0, count: 12)`
	`3`	`+ private var dp = [[Int]](repeating: [Int](repeating: -1, count: 12), count: 12)`
	`4`	`+`
	`5`	`+ func numberOf2sInRange(_ n: Int) -> Int {`
	`6`	`+ var n = n`
	`7`	`+ var len = 0`
	`8`	`+ while n > 0 {`
	`9`	`+ len += 1`
	`10`	`+ a[len] = n % 10`
	`11`	`+ n /= 10`
	`12`	`+ }`
	`13`	`+ for i in 0..<12 {`
	`14`	`+ dp[i] = [Int](repeating: -1, count: 12)`
	`15`	`+ }`
	`16`	`+ return dfs(len, 0, true)`
	`17`	`+ }`
	`18`	`+`
	`19`	`+ private func dfs(_ pos: Int, _ cnt: Int, _ limit: Bool) -> Int {`
	`20`	`+ if pos <= 0 {`
	`21`	`+ return cnt`
	`22`	`+ }`
	`23`	`+ if !limit && dp[pos][cnt] != -1 {`
	`24`	`+ return dp[pos][cnt]`
	`25`	`+ }`
	`26`	`+ let up = limit ? a[pos] : 9`
	`27`	`+ var ans = 0`
	`28`	`+ for i in 0...up {`
	`29`	`+ ans += dfs(pos - 1, cnt + (i == 2 ? 1 : 0), limit && i == up)`
	`30`	`+ }`
	`31`	`+ if !limit {`
	`32`	`+ dp[pos][cnt] = ans`
	`33`	`+ }`
	`34`	`+ return ans`
	`35`	`+ }`
	`36`	`+}`

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