3 Lookahead value

A lookahead value for a cell is the number of (cell-to-cell) moves to get to the closest destination cell. At a destination cell, the lookahead value is 0. The symbol for the lookahead value of a cell $c$ is denoted as $L(c)$.

The lookahead values of cells are important because when the mouse is at one cell, it can use the lookahead values of the neighboring cells to determine the best next move. In other words, the mouse always goes to the non-blocked neighboring cell with the least value.

A mouse may know the existence of some partitions. This permits the mouse to compute lookahead values in order to determine what to do in the next move.