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Fixed heapqueue.del for last elem (#5363)

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This commit is contained in:
Yuriy Glukhov
2017-02-10 11:15:43 +02:00
committed by Andreas Rumpf
parent a20b4c674e
commit 69fb2c6152
1 changed files with 34 additions and 13 deletions
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47
lib/pure/collections/heapqueue.nim
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@@ -77,8 +77,10 @@ proc pop*[T](heap: var HeapQueue[T]): T =
proc del*[T](heap: var HeapQueue[T], index: int) =
## Removes element at `index`, maintaining the heap invariant.
swap(seq[T](heap)[^1], seq[T](heap)[index])
seq[T](heap).setLen(heap.len - 1)
heap.siftup(index)
let newLen = heap.len - 1
seq[T](heap).setLen(newLen)
if index < newLen:
heap.siftup(index)
proc replace*[T](heap: var HeapQueue[T], item: T): T =
## Pop and return the current smallest value, and add the new item.
@@ -101,16 +103,19 @@ proc pushpop*[T](heap: var HeapQueue[T], item: T): T =
return item
when isMainModule:
proc toSortedSeq[T](h: HeapQueue[T]): seq[T] =
var tmp = h
result = @[]
while tmp.len > 0:
result.add(pop(tmp))
block: # Simple sanity test
var heap = newHeapQueue[int]()
let data = [1, 3, 5, 7, 9, 2, 4, 6, 8, 0]
for item in data:
push(heap, item)
doAssert(heap[0] == 0)
var sort = newSeq[int]()
while heap.len > 0:
sort.add(pop(heap))
doAssert(sort == @[0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
doAssert(heap.toSortedSeq == @[0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
block: # Test del
var heap = newHeapQueue[int]()
@@ -121,11 +126,27 @@ when isMainModule:
doAssert(heap[0] == 1)
heap.del(seq[int](heap).find(7))
heap.del(seq[int](heap).find(5))
heap.del(seq[int](heap).find(6))
heap.del(seq[int](heap).find(2))
doAssert(heap.toSortedSeq == @[1, 2, 3, 4, 5, 6, 8, 9])
var sort = newSeq[int]()
while heap.len > 0:
sort.add(pop(heap))
doAssert(sort == @[1, 3, 4, 8, 9])
heap.del(seq[int](heap).find(5))
doAssert(heap.toSortedSeq == @[1, 2, 3, 4, 6, 8, 9])
heap.del(seq[int](heap).find(6))
doAssert(heap.toSortedSeq == @[1, 2, 3, 4, 8, 9])
heap.del(seq[int](heap).find(2))
doAssert(heap.toSortedSeq == @[1, 3, 4, 8, 9])
block: # Test del last
var heap = newHeapQueue[int]()
let data = [1, 2, 3]
for item in data: push(heap, item)
heap.del(2)
doAssert(heap.toSortedSeq == @[1, 2])
heap.del(1)
doAssert(heap.toSortedSeq == @[1])
heap.del(0)
doAssert(heap.toSortedSeq == @[])