## Interview Question

Anonymous Interview*(Student Candidate)* Palo Alto, CA

Answer## Generate a new array from an array of numbers. Start from

the beginning. Put the number of some number first, and then that number. For example, from array 1, 1, 2, 3, 3, 1 You should get 2, 1, 1, 2, 2, 3, 1, 1 Write a program to solve this problem.

## Interview Answer

7 Answers

function numberArray( $arr ){

$a = array();

$number = null;

$c = -1;

foreach( $arr as $v ){

if( $v != $number ){

if( $number ){

$a[] = $c;

$a[] = $number;

}

$number = $v;

$c = 1;

} else {

++$c;

}

}

if( $c > 0 ){

$a[] = $c;

$a[] = $number;

}

return $a;

}

var_export( numberArray( array( 1,1,2,3,3,1 ) ) );

<?php

function foo($input) {

$len = count($input);

$toRet = array();

$idx = 0;

$current = null;

while ($idx < $len) {

$current = $input[$idx];

$currentCount = 0;

while ($current == $input[$idx]) {

$currentCount++;

$idx++;

}

$toRet[] = $currentCount;

$toRet[] = $current;

}

return $toRet;

}

$input = array(1);

for ($index = 0; $index < 10; $index++) {

$input = foo($input);

foreach ($input as $key=>$val) {

echo $val . "\t";

}

echo " \n";

}

?>

working in php:

<?

$list = array(1,1,2,3,3,1);

$result = numberArray($list);

print_r($result);

function numberArray($list){

$result = array();

$count = 1;

for($i=0;$i<sizeof($list)-1;$i++){

if(($i>sizeof($list)-2) || ($list[$i]!=$list[$i+1])){

$result[]=$count;

for($j=0;$j<$count;$j++)

$result[]=$list[$i];

$count=1;

}else{

$count++;

}

}

return $result;

}

?>

vector<int> reformat(int arr[], int size) {

vector<int> res;

int j, count = 0;

for(int i = 0; i < size; ) {

cout << i << endl;

count = 0;

for(j = i; j < size; j++) {

if(arr[j] != arr[i]) break;

count++;

}

res.push_back(count);

res.push_back(arr[i]);

i = j;

}

return res;

}

int i=0;

int j=1;

ArrayList<Integer> array=new ArrayList<Integer>();

while(i<givenArr.length)

{

j=1;

while(i!=givenArr.length-1 && givenArr[i+j]==givenArr[i])

j++;

array.add(j);

array.add(givenArr[i]);

i=i+j;

}

@Anonymous: Your inner while loop will cause an out-of-bounds exception to be thrown when your scanning hits the end of the array.

Your while loop will try to access givenArr[i+j] even when j increments to the point that surpasses the length of the array.

You need while((i+j) != givenArr.length ... )

## Add Answers or Comments

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int[] Reformat(int[] original, int length)

{

LinkedList<int> list = new LinkedList<int>();

int currentCount;

for(int i=0;i<length-1;i++)

{

if (original[i] != original[i+1])

{

list.Insert(original[i]);

list.Insert(currentCount);

currentCount = 0;

}

else

{

currentCount++;

}

}

int[] formattedList = new int[list.length];

for(int i=0;i<list.length;i++)

{

formattedList[i] = list.Remove;

}

return formattedList;

}

PrinceBoroujerdionOct 6, 2011