与 arrays arr1 和 arr2 匹配的最小移动次数）

Question

There are two arrays of integers arr1 and arr2. One move is defined as an increment or decrement by one of each digit of the items in the array. How many moves will it take to match the array arr1 with the array arr2? No reordering of the digits is allowed.

Example

arr1 = [123, 543]

arr2 = [321, 279]

Match arr1[0]=123 with arr2[0]=321.
Increment 1 twice to get 3 (2 moves) and decrement 3 twice to get 1 (2 moves).
4 moves are needed to match 123 with 321.
Match arr1[1]=543 with arr2[1]=279.
Decrement 5 three times to get 2 (3 moves) and increment 4 three times to get 7 (3 moves) and increment 3 six times to get 9 (6 moves).
12 moves are needed to match 543 with 279.
16 total moves are needed to match the arrays arr1 and arr2.

Constraints

1 ≤ n ≤ 105
1 ≤ arr1[i], arr2[i] ≤ 109
The lengths of arr1 and arr2 are equal, |arr1| = |arr2|.
The elements arr1[i] and arr2[i] have an equal number of digits.

Sample Case 0

Sample Input

STDIN Function

----- --------

2 → n = 2

1234 → arr1 = [1234,4321]

4321

2 → n = 2

2345 → arr2 = [2345,3214]

3214

Sample Output

10

Explanation

Match arr1[0]=1234 with arr2[0]=2345.
Increment 1 once to get 2 (1 move) and increment 2 once to get 3 (1 move)  Increment 3 once to get 4 (1 move)  and increment 4 once to get 5 (1 move).
4 moves are needed to match 1234 with 2345.
Match arr1[1]=4321 with arr2[1]=3214.
Decrement 4 once to get 3 (1 move) and decrement 3 once to get 2 (1 move) and decrement 2 once to get 1 (1 move) and increment 1 three times to get 3 (3 moves)
6 moves are needed to match 4321 with 3214.
6+4=10 total moves are needed to match the arrays arr1 and arr2.

Sample Case 1

Sample Input

STDIN Function

----- --------

1 → n = 1

2468 → arr1 = [2468]

1 → n = 1

8642 → arr2 = [8642]

Sample Output

16

Explanation

Match arr1[0]=2468 with arr2[0]=8642.
Increment 2 six times to get 8 (6 moves). Increment 4 twice to get 6 (2 moves). Decrement 6 twice to get 4 (2 moves). Decrement 8 six times to get 2  (6 moves).
16 moves are needed to match the arrays arr1 and arr2.

Ans :-

$a = [2468];
$b = [8642];
$n = count($a);

$result = 0; 

for ($i = 0; $i < $n; $i++)  
{ 
  $n1 = $a[$i]; 
  $n2 = $b[$i]; 
  while($n1 !=0){
     $r1 = $n1 % 10;
     $r2 = $n2 % 10;
     $n1 = $n1 /10;
     $n2 = $n2 /10;
     if($r1 > $r2){
         $result = $result + abs($r1 - $r2); 
     }
     if($r2 > $r1){
       $result = $result + abs($r2 - $r1); 
     }

  }

} 

echo  $result;

I don't know where I am wrong so please help me

Answer 1

split numbers to arrays of digits and find a positive difference between correspond digits

$arr1 = [1234,4321];
$arr2 = [2345,3214];

$sum = 0;
foreach(array_map(null, $arr1, $arr2) as list($x, $y)) {
    $x = str_split($x);
    $y = str_split($y);
    foreach(array_map(null, $x, $y) as list($a, $b)) {
        $sum += abs($a-$b);
    }
}
print($sum); // 10