org.jetbrains.kotlin.container.DataStructures.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2015 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.kotlin.container
import java.util.ArrayList
import java.util.HashSet
public fun topologicalSort(items: Iterable, dependencies: (T) -> Iterable): List {
val itemsInProgress = HashSet()
val completedItems = HashSet()
val result = ArrayList()
fun DfsVisit(item: T) {
if (item in completedItems)
return
if (item in itemsInProgress)
return //throw CycleInTopoSortException()
itemsInProgress.add(item)
for (dependency in dependencies(item)) {
DfsVisit(dependency)
}
itemsInProgress.remove(item)
completedItems.add(item)
result.add(item)
}
for (item in items)
DfsVisit(item)
return result.apply { reverse() }
}
public class CycleInTopoSortException : Exception()