Lecture 3

SoSe24/lec03_sort_alg/merge_plot.py

 from SoSe24.algodat.foundation import AlgoDatArray, AlgoDatValue, read_int_sequence, read_int_sequence_limited
 import matplotlib.pyplot as plt
+import merge_sort as ms
 
 
-def merge_sort(z: AlgoDatArray, storage: AlgoDatArray, left: int, right: int):
-    if left == right:
-        return
-    mid = (left + right) // 2
-    merge_sort(z, storage, left, mid)
-    merge_sort(z, storage, mid+1, right)
-    left_ptr = left
-    right_ptr = mid+1
-    storage_ptr = left
-    while left_ptr <= mid or right_ptr <= right:
-        if left_ptr <= mid and right_ptr <= right:
-            if z[left_ptr] < z[right_ptr]:
-                storage[storage_ptr].value = z[left_ptr].value
-                left_ptr += 1
-                storage_ptr += 1
-            else:
-                storage[storage_ptr].value = z[right_ptr].value
-                right_ptr += 1
-                storage_ptr += 1
-        elif left_ptr <= mid:
-            storage[storage_ptr].value = z[left_ptr].value
-            left_ptr += 1
-            storage_ptr += 1
-        else:
-            storage[storage_ptr].value = z[right_ptr].value
-            right_ptr += 1
-            storage_ptr += 1
-    for i in range(left, right+1):
-        z[i].value = storage[i].value
-
 
 if __name__ == "__main__":
     filename = "../../seq3.txt"
         AlgoDatValue.reset()
         z = read_int_sequence_limited(filename, right_end)
         storage = AlgoDatArray(z.size)
-        merge_sort(z, storage, 0, right_end-1)
+        ms.merge_sort(z, storage, 0, right_end-1)
         memory_values.append(AlgoDatValue.memory)
         compare_values.append(AlgoDatValue.compare)
 

SoSe24/lec03_sort_alg/quick_plot.py

+from SoSe24.algodat.foundation import AlgoDatArray, AlgoDatValue, read_int_sequence, read_int_sequence_limited
+import matplotlib.pyplot as plt
+import quick_sort as qs
+
+
+
+
+if __name__ == "__main__":
+    filename = "../../seq3.txt"
+    dummy = read_int_sequence("../../seq3.txt")
+    n = len(dummy)
+    step = n // 100
+
+    memory_values = []
+    compare_values = []
+
+    for right_end in range(1, n, step):
+        AlgoDatValue.reset()
+        z = read_int_sequence_limited(filename, right_end)
+        qs.quick_sort(z, 0, right_end-1)
+        memory_values.append(AlgoDatValue.memory)
+        compare_values.append(AlgoDatValue.compare)
+
+    plt.plot(range(1, n, step), memory_values, 'b', label='Memory')
+    plt.plot(range(1, n, step), compare_values, 'r', label='Compare')
+    plt.legend()
+    plt.show()

SoSe24/lec03_sort_alg/quick_sort.py

+from SoSe24.algodat.foundation import AlgoDatArray, AlgoDatValue, read_int_sequence
+from time import perf_counter as pfc
+
+def partition(z: AlgoDatArray, left: int, right: int) -> int:
+    global pivot
+    pivot.value  = z[right]
+    i = left
+    j = right - 1
+    while i < j:
+        while z[i] < pivot:
+            i += 1
+        while z[j] > pivot:
+            j -= 1
+        if i < j:
+            z[i], z[j] = z[j], z[i]
+            i += 1
+            j -= 1
+    if i==j and z[i] < pivot:
+        i += 1
+    if z[i] != pivot:
+        z[i], z[right] = z[right], z[i]
+    return i
+
+def quick_sort(z: AlgoDatArray, left: int, right: int):
+    if left < right:
+        q = partition(z, left, right)
+        quick_sort(z, left, q-1)
+        quick_sort(z, q+1, right)
+
+pivot = AlgoDatValue(0)
+
+if __name__ == "__main__":
+    z = read_int_sequence("../../seq0.txt")
+    print(z, len(z))
+    start = pfc()
+    quick_sort(z, 0, z.size-1)
+    print(z)
+    print(f"Dauer: {pfc() - start:.4f}s")
+    AlgoDatValue.summary()