PHP Exercises: Restore the original string by entering the compressed string with this rule

PHP: Exercise-72 with Solution

When character are consecutive in a string , it is possible to shorten the character string by replacing the character with a certain rule. For example, in the case of the character string YYYYY, if it is expressed as # 5 Y, it is compressed by one character.
Write a PHP program to restore the original string by entering the compressed string with this rule. However, the # character does not appear in the restored character string.
Note: The original sentences are uppercase letters, lowercase letters, numbers, symbols, less than 100 letters, and consecutive letters are not more than 9 letters.

Input: Multiple character strings are given. One string is given per line

Sample Solution: -

PHP Code:

$str  = "@88 + 1 = [email protected]";
    $index = 0;
    $result = array();
    while($index < strlen($str)) {
        $t = $str[$index++];
        if ($t == "@") {
            $len = $str[$index++];
            $char = $str[$index++];
            $run = "";
            for ($i = 0; $i < $len; $i++) {
                $run .= $char;
            $result[] = $run;
        } else {
            $result[] = $t;
    echo implode("", $result);

Sample Input:
@88 + 1 = [email protected]

Sample Output:

88888888 + 1 = 100000000


Flowchart: Read the mass data and find the number of islands.

PHP Code Editor:

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PHP: Tips of the Day

Why shouldn't I use mysql_* functions in PHP?

The MySQL extension:

  • Is not under active development
  • Is officially deprecated as of PHP 5.5 (released June 2013).
  • Has been removed entirely as of PHP 7.0 (released December 2015)
  • This means that as of 31 Dec 2018 it does not exist in any supported version of PHP. If you are using a version of PHP which supports it, you are using a version which doesn't get security problems fixed.
  • Lacks an OO interface
  • Doesn't support:
    • Non-blocking, asynchronous queries
    • Prepared statements or parameterized queries
    • Stored procedures
    • Multiple Statements
    • Transactions
    • The "new" password authentication method (on by default in MySQL 5.6; required in 5.7)
    • Any of the new functionality in MySQL 5.1 or later

Since it is deprecated, using it makes your code less future proof.

Lack of support for prepared statements is particularly important as they provide a clearer, less error-prone method of escaping and quoting external data than manually escaping it with a separate function call.

Ref : https://bit.ly/2BIIsF0