First Unique Character

Return the index of the first character in text that appears exactly once. Case matters.

Implement first_unique_index(text).

Input

text: The text to inspect.

Output

Return the index, or -1 if every character repeats.

Restricciones

0 ≤ length ≤ 100,000

Ejemplos

Entrada:
text = "swiss"

Salida esperada:
expected = 1

Entrada:
std::string text = "swiss";

Salida esperada:
long long expected = 1;

Entrada:
string text = "swiss";

Salida esperada:
long expected = 1;

Entrada:
text = "aabb"

Salida esperada:
expected = -1

Entrada:
std::string text = "aabb";

Salida esperada:
long long expected = -1;

Entrada:
string text = "aabb";

Salida esperada:
long expected = -1;

Referencias

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

• GWU CS1111 Introduction to Software Development - lab sequence