Suppose we have a sequence X_1, X_2, ..., X_n is fibonacci-like if −n >= 3X_i + X_{i+1} = X_{i+2} for all i + 2 = 3 otherwise return 0.Let us see the following implementation to get better understanding −Example Live Demo#include using namespace std; class Solution {    public:    int lenLongestFibSubseq(vector & A) {       int ret = 0;       unordered_map m;       int n = A.size();       vector < vector > dp(n, vector (n));       for(int i = 0; i < n; i++){       ... Read More

Suppose we have a positive integer N, we reorder the digits in any order (including the original order) such that the leading digit is non-zero. We have to check whether we can do this in a way such that the resulting number is a power of 2. So if the number is like 46, then the answer will be true.To solve this, we will follow these steps −Define a method called count, this will take x as inputret := 0while x is not 0ret := ret + 10 ^ last digit of xx := x / 10return retFrom the main ... Read More

Suppose we have to find the smallest prime palindrome that is greater than or equal to N. So if the N is 13, then the smallest palindrome will be 101.To solve this, we will follow these steps −If N is in range 8 to 11, then return 11for i in range 1 to 99999s := i as a stringr := sreverse rnum := concatenate s and substring of r from index 1, then convert to numberif num >= N and num is prime, then return numreturn 0Let us see the following implementation to get better understanding −Example Live Demo#include using ... Read More

Suppose we have a two dimensional matrix A where each value is 0 or 1. Here a move consists of choosing any row or column, and toggling each value in that row or column: changing all 0s to 1s, and all 1s to 0s. Now after making any number of moves, every row of this matrix is interpreted as a binary number, and the score of the matrix is the sum of these numbers. So our task is to find the highest possible score. If the input is like −001110101100The output will be 39 as after toggling, the matrix will ... Read More

PHP session can be used to prevent multiple inserts when submitting a form. PHP session sets a session variable (say $_SESSION['posttimer']) that sets the current timestamp on POST. Before processing the form in PHP, the $_SESSION['posttimer'] variable is checked for its existence and checked for a specific timestamp difference (say 2 or 3 seconds). This way, those insertions that are actually duplicates can be identified and removed.Simple form −// form.html         The reference to ‘my_session_file.php’ in the above will have the below lines of code −Exampleif (isset($_POST) && !empty($_POST)) {    if (isset($_SESSION['posttimer'])) {     ... Read More

This depends on the IDE that is being used. For example, Netbeans and IntelliJ can enable the usage of @var in a comment −/* @var $variable ClassName */ $variable->This way, the IDE would know that the ‘$variable’ is a class of the ClassName after the hint ‘->’ is encountered.In addition, an @return annotation can be created with a method that specifies that the return type will be an array of ClassName objects. This data can be accessed using a foreach loop that fetches the values of the objects −function get_object_type() {    return $this->values; } foreach( $data_object-> values as $object_attribute ... Read More

The ‘usort’ function can be used to sort multidimensional arrays in PHP. It sorts an array based on a user-defined criteria −Example Live DemoOutputThis will produce the following output −2 4 63 81An array with 4 elements is declared and this array is passed to the usort function, as well as calling the user-defined ‘my_sort’ function on the elements to make sure that the sorting takes place is ascending order.

The code is as follows −Example$object = new stdClass(); $object->name = "My name"; $myArray[] = $object;OutputThis will produce the following output −Suppose myArray already contains ‘a’ and ‘c’, the value of “My name” will be added to it. It becomes Array {    a:0, c:1, “My name”:2 }The object is created and then it is pushed to the end of the array (that was previously present).Alternative$myArray[] = (object) ['name' => 'My name'];

The language can’t be detected from the character type. There are other ways, but they don’t guarantee complete accuracy. The ‘TextLanguageDetect Pear Package’ can be used with decent accuracy. Below is a sample code for the same −Examplerequire_once 'Text/LanguageDetect.php'; $l = new Text_LanguageDetect(); $result = $l->detect($text, 4); if (PEAR::isError($result)) {    echo $result->getMessage(); } else {    print_r($result); }OutputThis will produce the following output −Array (    [german] => 0.407037037037    [dutch] => 0.288065843621    [english] => 0.283333333333    [danish] => 0.234526748971 )It is easy to use and has 52 language databases. But the downside is that the Eastern Asian languages can’t be detected using this package.

To read only 5 last lines of the text file, the code is as follows −Example$file = file("filename.txt"); for ($i = max(0, count($file)-6); $i < count($file); $i++) {    echo $file[$i] . ""; }OutputThis will produce the following output −Given that the file has more than 5 lines of text, the last 5 lines of the text file will be displayed.The file is opened and the number of lines in the file are counted, and beginning from the last line, 5 lines are read.