timsort

Basic-Scripts/timsort.py

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+# Python3 program to perform TimSort. 
+RUN = 32
+
+# This function sorts array from left index to 
+# to right index which is of size atmost RUN 
+def insertionSort(arr, left, right): 
+
+	for i in range(left + 1, right+1): 
+
+		temp = arr[i] 
+		j = i - 1
+		while j >= left and arr[j] > temp : 
+
+			arr[j+1] = arr[j] 
+			j -= 1
+
+		arr[j+1] = temp 
+
+# merge function merges the sorted runs 
+def merge(arr, l, m, r): 
+
+	# original array is broken in two parts 
+	# left and right array 
+	len1, len2 = m - l + 1, r - m 
+	left, right = [], [] 
+	for i in range(0, len1): 
+		left.append(arr[l + i]) 
+	for i in range(0, len2): 
+		right.append(arr[m + 1 + i]) 
+
+	i, j, k = 0, 0, l 
+	# after comparing, we merge those two array 
+	# in larger sub array 
+	while i < len1 and j < len2: 
+
+		if left[i] <= right[j]: 
+			arr[k] = left[i] 
+			i += 1
+
+		else: 
+			arr[k] = right[j] 
+			j += 1
+
+		k += 1
+
+	# copy remaining elements of left, if any 
+	while i < len1: 
+
+		arr[k] = left[i] 
+		k += 1
+		i += 1
+
+	# copy remaining element of right, if any 
+	while j < len2: 
+		arr[k] = right[j] 
+		k += 1
+		j += 1
+
+# iterative Timsort function to sort the 
+# array[0...n-1] (similar to merge sort) 
+def timSort(arr, n): 
+
+	# Sort individual subarrays of size RUN 
+	for i in range(0, n, RUN): 
+		insertionSort(arr, i, min((i+31), (n-1))) 
+
+	# start merging from size RUN (or 32). It will merge 
+	# to form size 64, then 128, 256 and so on .... 
+	size = RUN 
+	while size < n: 
+
+		# pick starting point of left sub array. We 
+		# are going to merge arr[left..left+size-1] 
+		# and arr[left+size, left+2*size-1] 
+		# After every merge, we increase left by 2*size 
+		for left in range(0, n, 2*size): 
+
+			# find ending point of left sub array 
+			# mid+1 is starting point of right sub array 
+			mid = left + size - 1
+			right = min((left + 2*size - 1), (n-1)) 
+
+			# merge sub array arr[left.....mid] & 
+			# arr[mid+1....right] 
+			merge(arr, left, mid, right) 
+
+		size = 2*size 
+
+# utility function to print the Array 
+def printArray(arr, n): 
+
+	for i in range(0, n): 
+		print(arr[i], end = " ") 
+	print() 
+
+
+# Driver program to test above function 
+if __name__ == "__main__": 
+
+	arr = [5, 21, 7, 23, 19] 
+	n = len(arr) 
+	print("Given Array is") 
+	printArray(arr, n) 
+
+	timSort(arr, n) 
+
+	print("After Sorting Array is") 
+	printArray(arr, n) 
+
+# This code is contributed by Rituraj Jain