When a heap is created to dynamically track a min value, after initialising an empty heap, do I actually need to call heapq.heapify(heap)? Or rather hq.heappop() and hp.heappush() will automatically do the job.. Thanks for the help!
import heapq as hp
heap = []
hp.heapify(heap) # is this line redundant?
for val in range(1, 100):
hp.heappush(heap, val)
print(heap[0])
Yep, in your case it's redundant. From the official doc here:
heapq.heappush(heap, item)
Push the value item onto the heap, maintaining the heap invariant.
heapq.heapify(x)
Transform list x into a heap, in-place, in linear time.
As you can see from the description of the heapify method, it's used for conversion of an existing list to a heap structure.
However, if you would like to keep the heap property of your data structure when adding new elements, then heappush is a way to go.
import heapq as hp
heap = []
for val in range(1, 100):
hp.heappush(heap, val)
print(heap[0])
However, if you would like to convert an existing array / list to a heap, then use the heapify method:
import heapq as hp
heap = []
for val in range(1, 100):
heap.append(val)
hp.heapify(heap)
print(heap[0])