Chess Square Color

Use a board whose top-left square is white. Rows and columns start at 0 at the top left. Adjacent squares alternate colors. Return empty text for a position outside the board.

Implement chess_square_color(column, row).

Input

column: The column, counted from the left starting at 0.

row: The row, counted from the top starting at 0.

Output

Return white, black, or an empty string for invalid coordinates.

Restricciones

−10 ≤ column, row ≤ 20. Valid board coordinates are 0 through 7.

Ejemplos

Entrada:
row = 3
column = 2

Salida esperada:
expected = "black"

Entrada:
long long row = 3;
long long column = 2;

Salida esperada:
std::string expected = "black";

Entrada:
long row = 3;
long column = 2;

Salida esperada:
string expected = "black";

Entrada:
row = 0
column = 8

Salida esperada:
expected = ""

Entrada:
long long row = 0;
long long column = 8;

Salida esperada:
std::string expected = "";

Entrada:
long row = 0;
long column = 8;

Salida esperada:
string expected = "";

Referencias

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

• #9 Chess Square Color