The description of the question is hard to understand but I am going to take a guess and assume you mean:
You have a 2D grid of tiles on a board, each tile being 32×32, and you can click anywhere on the board. You want to know which tile is being clicked.
std::vector is not helping you. Use a 2D array.
int tiles; // Board is 64 tiles wide and 96 tiles tall. You can make it any size you want.
Click.Pos = 459×761.
Clicked tile X = 459 / 32 = 14.
Clicked tile Y = 761 / 32 = 23.
Clicked tile = tiles.