RosettaCodeData/Task/Longest-increasing-subsequence/Swift/longest-increasing-subseque...

49 lines
970 B
Swift

import Foundation
extension Array where Element: Comparable {
@inlinable
public func longestIncreasingSubsequence() -> [Element] {
var startI = [Int](repeating: 0, count: count)
var endI = [Int](repeating: 0, count: count + 1)
var len = 0
for i in 0..<count {
var lo = 1
var hi = len
while lo <= hi {
let mid = Int(ceil((Double(lo + hi)) / 2))
if self[endI[mid]] <= self[i] {
lo = mid + 1
} else {
hi = mid - 1
}
}
startI[i] = endI[lo-1]
endI[lo] = i
if lo > len {
len = lo
}
}
var s = [Element]()
var k = endI[len]
for _ in 0..<len {
s.append(self[k])
k = startI[k]
}
return s.reversed()
}
}
let l1 = [3, 2, 6, 4, 5, 1]
let l2 = [0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15]
print("\(l1) = \(l1.longestIncreasingSubsequence())")
print("\(l2) = \(l2.longestIncreasingSubsequence())")