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3) Python program to left rotate the elements of an array

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IIn this program, we need to rotate the elements of an array towards the left by the specified number of times. In the left rotation, each element of the array will be shifted to its left by one position and the first element of the array will be added to end of the list. This process will be followed for a specified number of times.

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ARRAY 1

1   2  3  4  5  

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n=1

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ARRAY 2

2  3  4  5  1

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Consider above array, if n is 1 then, all elements of the array will be moved to its left by one position such that second element of the array will take the first position, the third element will be moved to the second position and so on. The first element of the array will be added to the last of the array.

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ALGORITHM:

  • STEP 1: Declare and initialize an array.

  • STEP 2: Variable n will denote the number of times an array should be rotated toward its left.

  • STEP 3: The array can be left rotated by shifting its elements to a position prior to them which can be accomplished by looping through the array and perform the operation arr[j] = arr[j+1].

  • STEP 4: The first element of the array will be added to the last of the rotated array.

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#Initialize array     

arr = [1, 2, 3, 4, 5];     

#n determine the number of times an array should be rotated    

n = 3;    

     

#Displays original array    

print("Original array: ");    

for i in range(0, len(arr)):    

    print(arr[i]),     

     

#Rotate the given array by n times toward left    

for i in range(0, n):    

    #Stores the first element of the array    

    first = arr[0];    

        

    for j in range(0, len(arr)-1):    

        #Shift element of array by one    

        arr[j] = arr[j+1];    

            

    #First element of array will be added to the end    

    arr[len(arr)-1] = first;    

     

print();    

     

#Displays resulting array after rotation    

print("Array after left rotation: ");    

for i in range(0, len(arr)):    

    print(arr[i]),    

4) Python program to print the duplicate elements of an array

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In this program, we need to print the duplicate elements present in the array. This can be done through two loops. The first loop will select an element and the second loop will iteration through the array by comparing the selected element with other elements. If a match is found, print the duplicate element.

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1    2   3  4   2   7   8   8   3  

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In the above array, the first duplicate will be found at index 4 which is the duplicate of the element (2) present at index 1. So, duplicate elements in the above array are 2, 3 and 8.

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ALGORITHM:

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  • STEP 1: Declare and initialize an array.

  • STEP 2: Duplicate elements can be found using two loops. The outer loop will iterate through the array from 0 to length of the array. The outer loop will select an element. The inner loop will be used to compare the selected element with the rest of the elements of the array.

  • STEP 3: If a match is found which means the duplicate element is found then, display the element.

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#Initialize array     

arr = [1, 2, 3, 4, 2, 7, 8, 8, 3];     

     

print("Duplicate elements in given array: ");    

#Searches for duplicate element    

for i in range(0, len(arr)):    

    for j in range(i+1, len(arr)):    

        if(arr[i] == arr[j]):    

            print(arr[j]);    

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