PHP Challenges: Find the single number which occurs odd number of times and other numbers occur even number of times

Last update on December 20 2024 10:22:27 (UTC/GMT +8 hours)

Write a PHP program to find the single number which occurs odd number of times and other numbers occur even number of times.

Input : 4, 5, 4, 5, 2, 2, 3, 3, 2, 4, 4

Explanation :

Sample Solution :

PHP Code :

<?php
// Function to find the element with odd occurrences in an array
function odd_occurrence($arr)
{
    // Initialize result variable to store the odd occurrence
    $result = 0;

    // Traverse the array
    foreach ($arr as &$value)
    {
        // Perform bitwise XOR operation
        // Bits that are set in $a or $b but not both are set.
        $result = $result ^ $value;
    }

    // Return the element with odd occurrences
    return $result;
}

// Test array
$num1 = array(4, 5, 4, 5, 2, 2, 3, 3, 2, 4, 4);

// Print the element with odd occurrences
print_r(odd_occurrence($num1) . "\n");
?>

Explanation:

Here is a brief explanation of the above PHP code:

• Function definition (odd_occurrence):
• The function "odd_occurrence()" takes an array '$arr' as input.
• It initializes a variable '$result' to store the result.
• Inside the function:
• It traverses the array using a foreach loop.
• For each element in the array, it performs a bitwise XOR operation (^) between the current element and the result.
• Bitwise XOR operation returns a bit that is set in either of the operands but not both. This helps find elements with odd occurrences efficiently.
• Function Call & Testing:
• The odd_occurrence function is tested with a test array '$num1'.
• The "print_r()" function prints the element with odd occurrences.

Sample Output:

2 

Flowchart:

PHP Code Editor:

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