sorting in python

Sort/Readme.md

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+username: aayushakrrana
+fullname: AAYUSH KUMAR RANA

Sort/mergesort.py

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+def mergeSort(alist):
+    print("Splitting ",alist)
+    if len(alist)>1:
+        mid = len(alist)//2
+        lefthalf = alist[:mid]
+        righthalf = alist[mid:]
+
+        mergeSort(lefthalf)
+        mergeSort(righthalf)
+
+        i=0
+        j=0
+        k=0
+        while i < len(lefthalf) and j < len(righthalf):
+            if lefthalf[i] < righthalf[j]:
+                alist[k]=lefthalf[i]
+                i=i+1
+            else:
+                alist[k]=righthalf[j]
+                j=j+1
+            k=k+1
+
+        while i < len(lefthalf):
+            alist[k]=lefthalf[i]
+            i=i+1
+            k=k+1
+
+        while j < len(righthalf):
+            alist[k]=righthalf[j]
+            j=j+1
+            k=k+1
+    print("Merging ",alist)
+
+list_of_elem = [54,26,93,17,77,31,44,55,20]
+mergeSort(list_of_elem)
+print(list_of_elem)

Sort/quicksort.py

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+def quicksort(arr):
+    less = []
+    equal = []
+    greater = []
+
+    if len(array) > 1:
+        pivot = array[-1]
+        for x in array:
+            if x < pivot:                less.append(x)
+            if x == pivot:               equal.append(x)
+            if x > pivot:                greater.append(x)
+
+    return quicksort(less) + equal + quicksort(greater) 

Sort/selection_sort.py

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+#Time complexity O(n^2) Space complexity O(n)
+
+def selection_sort(arr):
+    for i in range(len(arr)):
+        position_of_max = i
+        for j in range(i+1,len(arr)):
+            if arr[j]>arr[position_of_max]:
+                position_of_max = j
+        temp = arr[i]
+        arr[i] = arr[position_of_max]
+        arr[position_of_max] = temp
+    return arr
+
+arr = [13,4,12,1,5]
+print selection_sort(arr)