Happy tickets!
A bus ticket form a 1 a 2 a 3 a 4 a 5 a 6 in which 0 ⩽ a i ⩽ 9 .Tickets a 1 a 2 a 3 a 4 a 5 a 6 are called happy ticket if a 1 + a 2 + a 3 = a 4 + a 5 + a 6 .
Find how many happy tickets from 000000 to 999999?
The answer is 55252.
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<?php
$arr = range(0,9);
do{
$newarr = array();
foreach($arr as $a){
for($i=0;$i<=9;$i++){
$newarr[] = $a.$i;
}
}
$arr = $newarr;
} while(strlen($arr[0])<6);
$c=0;
foreach($arr as $a){
if($a[0]+$a[1]+$a[2]==$a[3]+$a[4]+$a[5]){
$c++;
}
}
echo $c; //55252
?>