How to use breadth first search/a* search to find the shortest path to the target?

I am working on a Snake AI game. I want to use BFS/A* to find the shortest path to the food. I know the coordinates of the food. There are other snakes on the board so I am trying to avoid them. I have the logic but how can I use BFS/A* to find the path? For example my snake's head's coordinate is (40,40) since i can only go left, right and up (no backwards as it is rest of my snake), how can I add these to my queue in BFS/A*? How can the BFS/A* expand? (It is 2D array type of board, nothing fancy). Output example: 1s and 4s are the snakes. 9 is the Food.

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 9 0 0 1 0 0 0 0 4 4 4 4 4 4
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 4
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

Each turn new coordinates are entered so the snakes movement. Aim is to use BFS/A* to locate food so snake can move towards it. BFS/A* will be used to determine my move. Help will be appreciated.

What I have tried:

I have sorted out the coordinates. I have my board size. So my input will be
(int[][] board Size, target coordinate x, target coordinate y, snake head x, snake head y)

Tags: Java, Game Development, Search, Path