# Php Program to Find closest number in array

• Last Updated : 27 Jul, 2022

Given an array of sorted integers. We need to find the closest value to the given number. Array may contain duplicate values and negative numbers.

Examples:

```Input : arr[] = {1, 2, 4, 5, 6, 6, 8, 9}
Target number = 11
Output : 9
9 is closest to 11 in given array

Input :arr[] = {2, 5, 6, 7, 8, 8, 9};
Target number = 4
Output : 5```

A simple solution is to traverse through the given array and keep track of absolute difference of current element with every element. Finally return the element that has minimum absolution difference.

An efficient solution is to use Binary Search.

## PHP

 `= ``\$arr``[``\$n` `- 1]) ` `        ``return` `\$arr``[``\$n` `- 1]; `   `    ``// Doing binary search ` `    ``\$i` `= 0;` `    ``\$j` `= ``\$n``;` `    ``\$mid` `= 0; ` `    ``while` `(``\$i` `< ``\$j``) ` `    ``{ ` `        ``\$mid` `= (``\$i` `+ ``\$j``) / 2; `   `        ``if` `(``\$arr``[``\$mid``] == ``\$target``) ` `            ``return` `\$arr``[``\$mid``]; `   `        ``/* If target is less than array element, ` `            ``then search in left */` `        ``if` `(``\$target` `< ``\$arr``[``\$mid``]) ` `        ``{ `   `            ``// If target is greater than previous ` `            ``// to mid, return closest of two ` `            ``if` `(``\$mid` `> 0 && ``\$target` `> ``\$arr``[``\$mid` `- 1]) ` `                ``return` `getClosest(``\$arr``[``\$mid` `- 1], ` `                                  ``\$arr``[``\$mid``], ``\$target``); `   `            ``/* Repeat for left half */` `            ``\$j` `= ``\$mid``; ` `        ``} `   `        ``// If target is greater than mid ` `        ``else` `        ``{ ` `            ``if` `(``\$mid` `< ``\$n` `- 1 && ` `                ``\$target` `< ``\$arr``[``\$mid` `+ 1]) ` `                ``return` `getClosest(``\$arr``[``\$mid``], ` `                                  ``\$arr``[``\$mid` `+ 1], ``\$target``); ` `            ``// update i ` `            ``\$i` `= ``\$mid` `+ 1; ` `        ``} ` `    ``} `   `    ``// Only single element left after search ` `    ``return` `\$arr``[``\$mid``]; ` `} `   `// Method to compare which one is the more close. ` `// We find the closest by taking the difference ` `// between the target and both values. It assumes ` `// that val2 is greater than val1 and target lies ` `// between these two. ` `function` `getClosest(``\$val1``, ``\$val2``, ``\$target``) ` `{ ` `    ``if` `(``\$target` `- ``\$val1` `>= ``\$val2` `- ``\$target``) ` `        ``return` `\$val2``; ` `    ``else` `        ``return` `\$val1``; ` `} `   `// Driver code ` `\$arr` `= ``array``( 1, 2, 4, 5, 6, 6, 8, 9 ); ` `\$n` `= sizeof(``\$arr``); ` `\$target` `= 11; ` `echo` `(findClosest(``\$arr``, ``\$n``, ``\$target``)); `   `// This code is contributed bu Sachin.` `?>`

Output:

`9`

Time Complexity: O(log(n))

Auxiliary Space: O(log(n)) (implicit stack is created due to recursion)

Please refer complete article on Find closest number in array for more details!

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