This is a curious exercise to understand the inner workings of heapq and why heapify is done. Experiment 1 from heapq import heappush, heappop data = [3,2,1] # heappush(data,4) heappop(data),heappop(data),heappop(data)#,heappop(data) Output: (3, 1, 2). What did heappop do to the list to make 1 and 2 swap positions? Which of the first two heappops did this? Experiment 2 (pushing 1 element + popping 1 more) data = [3,2,1] heappush(data,4) heappop(data),heappop(data),heappop(data),heappop(data) Output: (3, 1, 2, 4) Experiment 3 (change pushed element from 4 to 0) data = [3,2,1] heappush(data,0) heappop(data),heappop(data),heappop(data),heappop(data) Output:: (0, 1, 2, 3) Why when pushing 4, the output seems similar to experiment 1 (Please compare mechanics of experiment 1 and experiment 2), but when pushing 0, the other 3 elements also changed positions? It looks like pushing 0 instead of 4 turned the list into a real heap? P.s I know heapify(data) can turn experiment 3 output to (1, 2, 3, 4), making it work normally is not the point of the question. Continue reading...
