AlgoScope

Sift Down

AlgorithmintermediateHeap Operationsalso called heapify down, percolate down

Swap with the better child while a child outranks the value. One path, O(log n).

Decision · step 3 of 5Binary Heap: Extract the minimum
734286current2 > 6

Its right child 2 is smaller, so 6 sinks and 2 takes its place.

Open in the player →or start at step 3

What you will see

Compare both children, pick the smaller, swap, repeat downward.

How binary heap works →

Cost

BestO(1)
AverageO(log n)
WorstO(log n)
SpaceO(1)

How you work with it here

play it through, step one change at a time, scrub to any step, run it on your own input, predict what happens next, try operations in any order.

Screen readers: Nodes announce value, parent and children; each step announces the comparison and whether the value moves up or down.

Reduced motion: Swaps become value crossfades in both the tree and the array view.

Before this

Leads to

Topics that need this one first.

Taught by the same lesson

Binary Heap covers these too, in the same run.