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Code Array

Shuffle the array elements

The problem is to shuffle the elements of an array randomly. Shuffling an array means rearranging its elements in a random order. The goal is to achieve a random permutation of the array elements.


Consider the following array:

[1, 0, -3, 8, 7, 3, 9, 4, 2, 5, 10, 6]

After shuffling, the array may become:

[2, 8, 0, 4, 7, 3, 6, 10, 9, 5, 1, -3]


[3, 10, 6, 7, 4, 2, 1, 9, 0, 8, 5, -3]


[2, 7, 6, 5, -3, 0, 10, 9, 3, 4, 8, 1]

and so on.

Idea to Solve the Problem

To shuffle the array elements, we can use a simple approach known as the Fisher-Yates shuffle algorithm. The algorithm works by iterating through the array from the last element to the second element. For each element at index i, it randomly selects an index j between 0 and i (inclusive) and swaps the elements at indices i and j.

Algorithm (Fisher-Yates Shuffle)

  1. Start from the last element of the array and go up to the second element.
  2. For each element at index i, generate a random index j between 0 and i.
  3. Swap the elements at indices i and j.


function shuffle(arr):
    size = length of arr
    for i from size - 1 to 1:
        j = random location between 0 and i
        swap arr[i] with arr[j]
    end for
end function

Code Solution

Time Complexity

  • The time complexity of the Fisher-Yates shuffle algorithm is O(N), where N is the number of elements in the array. This is because we iterate through the array once, and for each iteration, we perform a constant-time swap operation.
  • Therefore, the overall time complexity of the shuffling algorithm is O(N), making it efficient for large arrays.

Resultant Output Explanation

The given Java program implements the Fisher-Yates shuffle algorithm to shuffle the array elements. It starts with an array of integer elements and shuffles the elements multiple times. The output displays the initial array elements before shuffling and the array elements after shuffling.

In the provided output, the initial array is [1, 0, -3, 8, 7, 3, 9, 4, 2, 5, 10, 6]. After each shuffle, the array elements are rearranged in a random order. The program executes the shuffle operation multiple times to show different possible shuffling outcomes. The final output displays the shuffled arrays.

Note: The specific order of the shuffled elements may vary each time the program is executed, as the shuffling is random.


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