i found an answer with a code but the code is wrong for this problem $,$ can you fix it please $?$

Question $3$

Consider an $nn$ grid. Set the coordinate system so that cell $(1,1)$ is at the bottom left and $(n,n)$ on the top right. Place

two robots on the grid: the first robot starts at $(1,1)$ and the second robot starts at $(n,n).$ In each time point, each robot

makes one step to a neighboring grid cell. The robots are not allowed to step off the grid. All grid cells apart from $(1,1)$ and

$(n,n)$ can be used at most once: a robot cannot step on a cell if either it or the other robot stepped on the cell previously.

The robots should not collide. The target of the robots is to swap positions: the first robot should reach $(n,n)$ and the second

robot should reach $(1,1).$

Write a BMC program that finds legal paths for the two robots from their sources to their destinations.

You are allowed to submit a pseudo code as a solution to this question. Alternatively, you are allowed to submit a code

snippet and its printout, as in Exercise $3.$

we need a list of all paths that the robots would swap places without colliding $,$ could this be a bfs$/$dfs problem $?$