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// Top and bottom N max/min items from an Array, with no need to sort
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---------- | |
541 | |
141 | |
18 | |
---------- | |
540 | |
16 | |
---------- | |
-7 | |
2 | |
16 | |
---------- | |
17 | |
540 | |
---------- | |
10000000 | |
9999999 | |
9999998 | |
---------- | |
10000000 | |
9999999 | |
9999998 | |
---------- | |
0 | |
1 | |
2 | |
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// Top and bottom N max/min items from an Array, with no need to sort | |
object TopBottomN extends App { | |
def bottomN(a: Array[Int], n: Int): Array[Int] = { | |
val smallestVals = Array.fill(n)(Int.MaxValue) | |
a.foreach { number => | |
var inserted=false | |
(n - 1 to 0 by -1).foreach { pos => | |
if (smallestVals(pos) > number && !inserted) { | |
(0 to pos - 1).foreach { x => smallestVals(x) = smallestVals(x + 1) } | |
smallestVals(pos) = number | |
inserted=true | |
} | |
} | |
} | |
smallestVals.filterNot(_==Int.MaxValue).reverse | |
} | |
def topN(a: Array[Int], n: Int): Array[Int] = { | |
val largestVals = Array.fill(n)(Int.MinValue) | |
a.foreach { number => | |
var inserted=false | |
(n - 1 to 0 by -1).foreach { pos => | |
if (largestVals(pos) < number && !inserted) { | |
(0 to pos - 1).foreach { x => largestVals(x) = largestVals(x + 1) } | |
largestVals(pos) = number | |
inserted=true | |
} | |
} | |
} | |
largestVals.filterNot(_==Int.MinValue).reverse | |
} | |
println("-"*10) | |
topN(Array(141, 1, 17, -7, 18, 541), 3).foreach(println) | |
println("-"*10) | |
topN(Array(16, 540), 3).foreach(println) | |
println("-"*10) | |
bottomN(Array(131, 2, 16, -7, 18, 542), 3).foreach(println) | |
println("-"*10) | |
bottomN(Array(17, 540), 3).foreach(println) | |
val bigNum=10000000 | |
println("-"*10) | |
topN((0 to bigNum).toArray, 3).foreach(println) | |
println("-"*10) | |
topN((bigNum to 0 by -1).toArray, 3).foreach(println) | |
println("-"*10) | |
bottomN((0 to bigNum).toArray, 3).foreach(println) | |
} |
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