Is éard is binary heap ann ná crann dhénártha iomlán atá stóráilte in array a choinníonn an heap property: i min-heap, tá gach páirent ≤ a leanaí, agus dá bhrí sin tá an íosmhéan i gcónaí ag an bhfréamh. Is í seo an priority queue a chur i bhfeidhm go caighdeánach.
1 index: 0 1 2 3 4
/ \ array: [1, 3, 5, 8, 4]
3 5 parent(i) = (i-1)//2
/ \ left(i) = 2i+1
8 4 right(i) = 2i+2
import heapq
h = []
heapq.heappush(h, 5) # O(log n) — bubble up
heapq.heappush(h, 1)
heapq.heappush(h, 3)
smallest = h[0] # peek min -> O(1)
heapq.heappop(h) # O(log n) — remove root, sift down -> 1
| Operation | Time |
|---|---|
| peek min/max | O(1) |
| push (insert) | O(log n) |
| pop (extract) | O(log n) |
| build heap from n items | O(n) |
Tugann heap an geal is tábhachtaí eile duit ar an toirt gan gach rud a bhheith sórtáilte go hiomlán, atá i bhfad níos saoire ná athannadh.
Is é seo an bhunús algartaim thógtha ar thosaíochta agus uirlis dhéanúsach agus ea le haghaidh ceisteanna "k is mó/is lú".