Merge pull request #94 from dsrao711/issue-91

Completed issue - 91 : Added python code for DSA 450

Author: smv1999

DSA 450 GFG/max_and_min_of_array.py

@@ -0,0 +1,44 @@
+# Maximum and minimum of an array using minimum number of comparisons - Python
+
+def getMinMax(arr):
+	
+	n = len(arr)
+	
+	# If array has even number of elements then initialize the first two elements as minimum and maximum
+	if(n % 2 == 0):
+		maximum = max(arr[0], arr[1])
+		minimum = min(arr[0], arr[1])
+		
+		# set the starting index for loop
+		i = 2
+		
+	# If array has odd number of elements then initialize the first element as minimum and maximum
+	else:
+		maximum = minimum = arr[0]
+		
+		# set the starting index for loop
+		i = 1
+		
+	# In the while loop, pick elements in pair and compare the pair with max and min so far
+	while(i < n - 1):
+		if arr[i] < arr[i + 1]:
+			maximum = max(maximum, arr[i + 1])
+			minimum = min(minimum, arr[i])
+		else:
+			maximum = max(maximum, arr[i])
+			minimum = min(minimum, arr[i + 1])
+			
+		# Increment the index by 2 as two elements are processed in loop
+		i += 2
+	
+	return (maximum, minimum)
+	
+# Driver Code
+if __name__ =='__main__':
+	
+	arr = [9, 1, 45, 2, 330, 3]
+	maximum, minimum = getMinMax(arr)
+	print("Minimum element is", minimum)
+	print("Maximum element is", maximum)
+	
+

DSA 450 GFG/move_all_neg_numbers.py

@@ -0,0 +1,17 @@
+
+
+def rearrange (arr , n ):
+    j = 0 
+    for i in range(0 , n)  :
+        if(arr[i] < 0):
+            temp = arr[i]
+            arr[i] = arr[j]
+            arr[j] = temp 
+            j = j + 1
+    print(arr)
+    
+#Driver code 
+sequence = [1 , 3, - 6 , 9 , -3 , -1]
+length = len(sequence)
+print(sequence.sort)
+rearrange(sequence , length)

DSA 450 GFG/reverse_an_array.py

@@ -0,0 +1,22 @@
+#  Write a program to reverse an array
+# Given an array (or string), the task is to reverse the array/string.
+# Examples : 
+ 
+# Input  : arr[] = [1, 2, 3]
+# Output : arr[] = [3, 2, 1]
+# Input :  arr[] = [4, 5, 1, 2]
+# Output : arr[] = [2, 1, 5, 4]
+
+
+
+
+# Reverse of an array can be implented in Python using the List slicing 
+
+def reverseList(a):
+      print( a[::-1])
+
+# Driver Code
+arr = [4,5,1,2]
+print(arr)
+print("Reverse : ")
+reverseList(arr)