Extract Operation

To extract the minimum (in a min-heap):

$1.$ Save the root value.

$2.$ Move the last element to the root.

$3.$ "Bubble down": while larger than a child, swap with the smaller child.

$4.$ Return the saved value.

function extractMin(heap)
    minVal := heap[0]
    heap[0] := last element of heap
    remove last element
    bubbleDown(heap, 0)
    return minVal

Bubbling down takes at most $O(\log n)$ swaps.