Computer Science / Binary Heap Dynamics
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LABORATORY 08 · COMPUTER SCIENCE

Empirical Analysis of Binary Heaps and Priority Queues: In-Place Floyd's Heapify, Sift-Down / Sift-Up Asymptotics, and Priority Event Scheduling

Determine the heapify comparison scaling factor k_heap and evaluate priority queue mechanics, verifying Floyd's linear O(n) construction bound C(n) = 2(n − log₂ n) and examining sift-down versus sift-up asymptotes. Explore interactive search algorithms, compare operation counts and analyse complexity scaling.

COMPUTE · BENCHMARK · ANALYSE

Your virtual algorithm laboratory.

HEAPIFY COMPARISONS (C)—
EXECUTION STATUS

Ready to execute Array Size benchmark.

512 keys
Unordered array initialized with randomized permutations of distinct keys in range [1, 10000].

Adjust Array Size n, then execute benchmark.

Operation counts are generated deterministically by the exact algorithmic execution model. Modern hardware benchmarks additionally reflect cache line prefetching and branch misprediction penalties.

Algorithmic assumptions and limits

The simulated execution model evaluates idealized complete binary heaps where Floyd's bottom-up construction on power-of-two arrays executes with exact comparison counts C(n) = 2(n − log₂ n). In physical computer systems, heap throughput is modulated by CPU memory bus bandwidth contention, non-local cache line eviction penalties during deep sifting, branch predictor mispredictions during child selection comparisons, and OS thread preemption. The simulated benchmark environment reflects strict deterministic execution of Floyd's bottom-up in-place build_heap algorithm on power-of-two arrays of size n = 2^k. Each non-leaf node i from ⌊n/2⌋ − 1 down to 0 is sifted down along the path of maximum children. At each level of the sift path, exactly 2 key comparisons occur: one comparison between the left and right children to select the larger child, and one comparison between the parent and the selected larger child. For an array of size n = 2^k, summing these comparisons across all levels yields the exact closed-form combinatorial identity C(n) = 2n − 2 log₂(n) comparisons. Defining the cumulative sift interval coordinate x = n − log₂(n) yields the exact linear model C = 2.0000 · x + 0.0000 comparisons, providing an ideal microarchitectural testbed for Ordinary Least-Squares regression with R² = 1.000000.

Computational tools & environment.

Contiguous Heap Array Buffer

Sequential memory allocation mapping an implicit complete binary tree into contiguous physical RAM with parent-child indexing arithmetic.

Floyd Bottom-Up Heapifier

In-place algorithmic construction unit sifting nodes downward from index ⌊n/2⌋ − 1 down to 0 to establish the heap invariant in linear O(n) time.

Sift-Down / Sift-Up Comparator

Hardware-coordinated comparator register tracking discrete child-child and parent-child decision branches during element restoration.

Priority Event Scheduler Queue

Discrete event simulation engine utilizing a Min-Heap to manage chronological event dispatching in operating systems and network queues.

Cache Stride Telemetry Monitor

Virtual memory profiler measuring non-local child index jumps (2i + 1, 2i + 2) across CPU L1/L2 cache lines during deep heap traversals.

D-Ary Heap Configuration Module

Algorithmic parameter controller evaluating 4-way and d-ary heap fan-out architectures to balance tree height with child comparison costs.

FOLLOW THE METHOD

A reason behind every step.

Determine the heapify comparison scaling factor k_heap and evaluate priority queue mechanics, verifying Floyd's linear O(n) construction bound C(n) = 2(n − log₂ n) and examining sift-down versus sift-up asymptotes. Suggested independent settings: 64, 128, 256, 512, 1024, 2048, 4096 keys.

01

Initialize Contiguous Array Buffer & Key Permutations

Allocate a contiguous array buffer of n distinct 64-bit integer keys arranged in randomized permutation order, verifying zero auxiliary pointer allocation.

02

Select Benchmark Scale Range

Adjust the independent variable control slider to choose an array size n between 64 and 4,096 keys across the designated power-of-two benchmark settings.

03

Execute Floyd Bottom-Up Heapify

Trigger the in-place construction engine, initiating bottom-up sift-down passes from index ⌊n/2⌋ − 1 down to 0 to establish the Max-Heap invariant.

04

Measure Discrete Key Comparisons

Read the deterministic comparison count C from the comparator register, verifying that C matches exactly 2n − 2 log₂(n) comparisons, and record the reading.

05

Repeat Across Full Scale Range

Systematically iterate through all 7 power-of-two scales (n = 64, 128, 256, 512, 1024, 2048, and 4096 keys), recording key comparisons and cumulative sift space.

06

Perform OLS Regression & Priority Scheduling Analysis

Plot key comparisons C against cumulative sift interval space x = n − log₂(n), perform Ordinary Least-Squares regression to compute k_heap, and evaluate scheduler throughput.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into asymptotic insight.

See a complete example report ↗

Points are your recorded benchmark observations. The regression line validates Binary Heap Dynamics complexity scaling.

LINEAR ASYMPTOTIC FIT · y = mx + b
C = k_heap · (n − log₂(n)) + C₀
#Array Size (n) (keys)Heapify Comparisons (C) (comparisons)Cumulative Sift Interval Space x = n − log₂(n) (intervals)Key Comparisons y = C (comparisons)Remove

No readings yet. Execute a Array Size benchmark and record it.

Calculate it yourself.

CHECK YOUR UNDERSTANDING

Explain what the operation counts mean.

What is the worst-case time complexity of building a Binary Heap of n elements using Floyd's bottom-up build_heap algorithm?

In a 0-indexed contiguous array representing a Complete Binary Heap, what are the child indices of a node stored at index i?

Why does Heapsort typically execute slower than Quicksort on modern microprocessors, despite both having O(n log n) asymptotic complexity?

How many key comparisons occur in the worst case at each step of Sift-Down (sink) in a Binary Max-Heap?