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2981. Find Longest Special Substring That Occurs Thrice I

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	`1`	`+class Solution {`
	`2`	`+`
	`3`	`+ // Solution by Sergey Leschev`
	`4`	`+ // 2981. Find Longest Special Substring That Occurs Thrice I`
	`5`	`+`
	`6`	`+ // Time complexity: O(N)`
	`7`	`+ // Space complexity: O(N)`
	`8`	`+`
	`9`	`+ func maximumLength(_ s: String) -> Int {`
	`10`	`+ var count = 0`
	`11`	`+ var last = s[s.startIndex]`
	`12`	`+ var ans = 0`
	`13`	`+ var ump = [Character: [Int]]()`
	`14`	`+`
	`15`	`+ for c in s {`
	`16`	`+ if c == last {`
	`17`	`+ count += 1`
	`18`	`+ } else {`
	`19`	`+ if ump[last] == nil {`
	`20`	`+ ump[last] = [count]`
	`21`	`+ } else {`
	`22`	`+ ump[last]?.append(count)`
	`23`	`+ }`
	`24`	`+ count = 1`
	`25`	`+ last = c`
	`26`	`+ }`
	`27`	`+ }`
	`28`	`+ if ump[last] == nil {`
	`29`	`+ ump[last] = [count]`
	`30`	`+ } else {`
	`31`	`+ ump[last]?.append(count)`
	`32`	`+ }`
	`33`	`+`
	`34`	`+ for (k, v) in ump {`
	`35`	`+ var l1 = 0`
	`36`	`+ var l2 = 0`
	`37`	`+ var l3 = 0`
	`38`	`+`
	`39`	`+ for e in v {`
	`40`	`+ if l1 < e {`
	`41`	`+ l3 = l2`
	`42`	`+ l2 = l1`
	`43`	`+ l1 = e`
	`44`	`+ } else if l2 < e {`
	`45`	`+ l3 = l2`
	`46`	`+ l2 = e`
	`47`	`+ } else if l3 < e {`
	`48`	`+ l3 = e`
	`49`	`+ }`
	`50`	`+ }`
	`51`	`+`
	`52`	`+ if l1 == l2 && l1 > l3 {`
	`53`	`+ l2 -= 1`
	`54`	`+ }`
	`55`	`+`
	`56`	`+ if l1 + l2 + l3 >= 3 {`
	`57`	`+ ans = max(ans, l1 - 2, l2)`
	`58`	`+ }`
	`59`	`+ }`
	`60`	`+`
	`61`	`+ return ans != 0 ? ans : -1`
	`62`	`+ }`
	`63`	`+}`

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