PHP Exercises: Print out the sum of pairs of numbers of a given sorted array of positive integers that is equal to a given number

Last update on May 26 2025 13:16:37 (UTC/GMT +8 hours)

44. Sum of Number Pairs in Sorted Array

Write a PHP program to print out the sum of pairs of numbers of a given sorted array of positive integers which is equal to a given number.

Sample Solution:

PHP Code:

<?php
// Define a function to find pairs in an array that sum up to a given value
function find_Pairs($nums, $pair_sum) {
    // Initialize an empty string to store pairs
    $nums_pairs = "";

    // Iterate through each element in the array
    for ($i = 0; $i < count($nums); $i++) {
        // Iterate through subsequent elements to find pairs
        for ($j = $i + 1; $j < count($nums); $j++) {
            // Check if the sum of the current pair equals the target sum
            if ($nums[$i] + $nums[$j] == (int)$pair_sum) {
                // Concatenate the pair to the result string
                $nums_pairs .= $nums[$i] . "," . $nums[$j] . ";";
            }
        }
    }

    // Return the string containing pairs
    return $nums_pairs;
}

// Test the function with example array and pair sums
$nums = array(0, 1, 2, 3, 4, 5, 6);
echo find_Pairs($nums, 7)."\n";
echo find_Pairs($nums, 5)."\n";

?>

Explanation:

Function Definition:

The function find_Pairs($nums, $pair_sum) is designed to find pairs of numbers in the array $nums that sum up to the specified value $pair_sum.

Initialize Result Variable:

A string variable $nums_pairs is initialized to store the pairs of numbers that meet the criteria.

Outer Loop:

A for loop iterates through each element in the array $nums using the index variable $i.

Inner Loop:

A nested for loop iterates through the subsequent elements of the array starting from the index $i + 1, using the index variable $j.

Check for Pair Sum:

Inside the inner loop, an if statement checks if the sum of the elements at indices $i and $j equals the target sum (int)$pair_sum.
If they do, the pair (in the format "num1,num2;") is concatenated to the $nums_pairs string.

Return Pairs:

After checking all possible pairs, the function returns the string containing the pairs that add up to the target sum.

Output:

1,6;2,5;3,4;                                                
0,5;1,4;2,3;

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to identify all unique pairs in a sorted array that sum up to a given target value.
Write a PHP script to use the two-pointer technique to efficiently find pairs whose sum equals a specified number.
Write a PHP function to output every pair of numbers from a sorted array that meets a specified summation condition.
Write a PHP script to compute and display all unique pairs from a sorted array that total a given sum.

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