Review Merge-Lösung und Vergleichsplot

praktika/02_merge_sort/compare_sorts.py

@@ -0,0 +1,47 @@
+import sys
+import os
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)), '..', '..'))
+
+import matplotlib.pyplot as plt
+from utils.algo_context import AlgoContext
+from utils.algo_array import Array
+from vorlesung.L03_fortgeschrittenes_sortieren.quick_sorting import quick_sort
+from vorlesung.L03_fortgeschrittenes_sortieren.heap_sorting import heap_sort
+from merge_sorting import merge_sort
+
+SIZES = list(range(10, 210, 10))
+
+algorithms = [
+    ("Quicksort",  quick_sort),
+    ("Heapsort",   heap_sort),
+    ("Merge Sort", merge_sort),
+]
+
+comparisons = {name: [] for name, _ in algorithms}
+writes      = {name: [] for name, _ in algorithms}
+
+for name, sort_func in algorithms:
+    ctx = AlgoContext()
+    for n in SIZES:
+        ctx.reset()
+        z = Array.random(n, -1000, 1000, ctx)
+        sort_func(z, ctx)
+        comparisons[name].append(ctx.comparisons)
+        writes[name].append(ctx.writes)
+
+fig, (ax1, ax2) = plt.subplots(2, 1, figsize=(10, 8), sharex=True)
+
+for name in comparisons:
+    ax1.plot(SIZES, comparisons[name], label=name, marker='o', markersize=3)
+ax1.set_ylabel("Vergleiche")
+ax1.set_title("Quicksort vs. Heapsort vs. Merge Sort")
+ax1.legend()
+
+for name in writes:
+    ax2.plot(SIZES, writes[name], label=name, marker='o', markersize=3)
+ax2.set_ylabel("Schreibzugriffe")
+ax2.set_xlabel("n")
+ax2.legend()
+
+plt.tight_layout()
+plt.show()

praktika/02_merge_sort/merge_sorting.py

@@ -15,9 +15,9 @@ def merge_sort_stepwise(z: Array, ctx: AlgoContext, l=None, r=None, buffer=None)
         m = (l + r) // 2
         yield from merge_sort_stepwise(z, ctx, l, m, buffer)
         yield from merge_sort_stepwise(z, ctx, m + 1, r, buffer)
-        yield from merge(z, ctx, l, m, r, buffer)
+        yield from merge(z, l, m, r, buffer)
 
-def merge(z: Array, ctx: AlgoContext, l: int, m: int, r: int, buffer: Array):
+def merge(z: Array, l: int, m: int, r: int, buffer: Array):
     i, j, k = l, m + 1, l
     while i <= m and j <= r:
         if z[i] <= z[j]: