/
mergeKSortedLists.kt
54 lines (51 loc) · 1.53 KB
/
mergeKSortedLists.kt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
import kotlinx.coroutines.Job
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.joinAll
import kotlinx.coroutines.launch
import java.util.*
fun mergeTwoSortedLists(list1: List<Int>, list2: List<Int>): List<Int> {
var index1 = 0
var index2 = 0
val result = mutableListOf<Int>()
while(index1 < list1.size && index2 < list2.size) {
if(list1[index1] < list2[index2]) {
result.add(list1[index1])
index1 += 1
} else {
result.add(list2[index2])
index2 += 1
}
}
result.addAll(list1.slice(index1 until list1.size))
result.addAll(list2.slice(index2 until list2.size))
return result.toList()
}
suspend fun concurrentlyMergeKSortedLists(lists: List<List<Int>>): List<Int> = coroutineScope {
val channel = Channel<List<Int>>(1)
val jobs = mutableListOf<Job>()
repeat(lists.size) {
jobs.add(
launch {
channel.send(lists[it])
}
)
}
repeat(lists.size - 1) {
jobs.add(
launch {
channel.send(mergeTwoSortedLists(channel.receive(), channel.receive()))
}
)
}
jobs.joinAll()
channel.receive()
}
fun mergeKSortedLists(lists: List<List<Int>>): List<Int> {
val queue = ArrayDeque<List<Int>>()
lists.forEach { queue.add(it) }
while(queue.size > 1) {
queue.addLast(mergeTwoSortedLists(queue.removeFirst(), queue.removeFirst()))
}
return queue.removeFirst()
}