Count Numbers With Distinct Neighbors

Count integers from left through right, including both endpoints, that have no equal neighboring digits. Use their usual decimal writing with no leading zeroes. Zero and all other single-digit numbers qualify.

Implement counting_numbers(left, right).

Input

left: The first allowed value.

right: The last allowed value.

Output

Return how many values satisfy the rule.

Restricciones

0 ≤ left ≤ right ≤ 10¹⁸. The range may be too large to inspect each integer individually.

Ejemplos

Entrada:
left = 10
right = 15

Salida esperada:
expected = 5

Entrada:
long long left = 10;
long long right = 15;

Salida esperada:
long long expected = 5;

Entrada:
long left = 10;
long right = 15;

Salida esperada:
long expected = 5;

Entrada:
left = 0
right = 9

Salida esperada:
expected = 10

Entrada:
long long left = 0;
long long right = 9;

Salida esperada:
long long expected = 10;

Entrada:
long left = 0;
long right = 9;

Salida esperada:
long expected = 10;

Referencias

Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.

• Counting Numbers — 2220