hackerrank-php

List of solved Hackerrank challenges in PHP language

Practice > Algorithms > Warmup

• Solve me first

function solveMeFirst($a,$b){
	return $a + $b;
}

• Simple Array Sum

function simpleArraySum($ar) {
    $sum = 0;
    foreach($ar as $value){
        $sum+=$value;
    }
    return $sum;
}

• Compare the Triplets

function compareTriplets($a, $b) {
    $length = count($a);
    $aliceScore = 0;
    $bobScore = 0;
    for($i=0; $i<$length; $i++){
        if($a[$i] == $b[$i]){
            continue;
        }
        if($a[$i] > $b[$i]){
            $aliceScore++;
            continue;
        }
        $bobScore++;
    }
    return [$aliceScore, $bobScore];
}

• A Very Big Sum

function aVeryBigSum($ar) {
    $sum = 0;
    foreach($ar as $value){
        $sum+=$value;
    }
    return $sum;
}

• Diagonal Difference

function diagonalDifference($arr) {
    $length = count($arr);
    $primaryDiagonal = 0;
    $secondaryDiagonal = 0;
    $lastIndex = $length - 1;
    for($i = 0; $i<$length; $i++){
        $primaryDiagonal+=$arr[$i][$i];
        $secondaryDiagonal+=$arr[$i][$lastIndex--];
    }
    return abs($primaryDiagonal - $secondaryDiagonal);
}

• Plus Minus

function plusMinus($arr) {
    $POSITIVES = 0;
    $NEGATIVES = 1;
    $ZEROES = 2;

    $length = count($arr);
    // declare the temp numbers to index positions
    $numbers = [0, 0, 0];

    // determine the plusMinus of the numbers
    foreach($arr as $val){
        if($val === 0){
            $numbers[$ZEROES] = $numbers[$ZEROES] + 1;
            continue;
        }
        if($val > 0){
            $numbers[$POSITIVES] = $numbers[$POSITIVES] + 1;
            continue;
        }
        $numbers[$NEGATIVES] = $numbers[$NEGATIVES] + 1;
    }

    $plusMinusArr = array_map(function ($number) use ($length) {
        return number_format($number/$length, 6);
    }, $numbers);

    foreach($plusMinusArr as $plusMinus){
        echo $plusMinus;
        echo "\n";
    }
}

• Staircase

function staircase($n) {
    $totalSteps = $n;
    $staircase = [];
    // start from the right steps
    for($n; $n>0; $n--){
        $stairs = [];
        // proceed from left stair until the reach the final stair steps
        // then gradually increase the starting stair
        for($i=1; $i<=$n; $i++){
            // if it reached the final step print the stairs "#" else the its spaces
            if($i == $n){
                // calculate the total stairs to print
                $totalPrintOfStairs = ($totalSteps - $n) + 1;
                for($totalPrintOfStairs; $totalPrintOfStairs>0; $totalPrintOfStairs--){
                 array_push($stairs, "#");
                }
                array_push($staircase, $stairs);
                break;
            }
            array_push($stairs, " ");
        }
    }

    // print the staircases
    foreach($staircase as $stairs){
        foreach($stairs as $stair){
            echo $stair;
        }
        echo "\n";
    }
}

• Mini-Max Sum

function miniMaxSum($arr) {
    $maxSumTempArr = $arr;
    $minSumTempArr = $arr;

    // sort into ascending order and get the first four values
    sort($minSumTempArr);
    $minSumArr = array_splice($minSumTempArr, 0 ,4);

    // sort into descending order and get the first four values
    rsort($maxSumTempArr);
    $maxSumArr = array_splice($maxSumTempArr, 0, 4);    

    echo array_sum($minSumArr) . ' ' . array_sum($maxSumArr);
}

• Birthday Cake Candles

function birthdayCakeCandles($ar) {
   // count the recurring of the candle
   $candles = array_count_values($ar);
   // sort the recurring candle by descending & get the most recurring candle
   krsort($candles);
   $candlesBlowsValue = array_values($candles);
   return $candlesBlowsValue[0];
}

• Time Conversion

function timeConversion($s) {
    $strToTime = strtotime($s);
    return date('H:i:s', $strToTime);
}

• Grading Students

function gradingStudents($grades) {
     $MODULO = 5;
     $finalGrades = [];

     $finalGrades = array_map(function($grade) use ($MODULO){
         // get the next multiplier by 5
         $nextMultiplier = $grade + ($MODULO - $grade % $MODULO);
         $difference = $nextMultiplier - $grade;
         // do not round up if grade less than 40 
         // the difference is 3 and greater than 3
         if($nextMultiplier < 40 || $difference === 3 || $difference > 3){
             return $grade;
         }
         
         // round up if the difference is less than 3
         return $nextMultiplier;
     }, $grades);

     return $finalGrades;
}