In A* algorithm, There seems to be a problem when putting neighboring nodes into heap

[ProofNight]

In the astar.cpp file, costs receive the map as a one-dimensional array.
This program uses the manhattan distance.
Select nodes up, down, left, and right through +i, -i, +nx_, and -nx_ at 68:71 line.
In the case of nodes at the edge of the map, simply using +i and -i will select the opposite node of the upper or lower line, respectively, so a conditional statement is required.

The code below is the code I modified

    if(i%nx_!=0)    add(costs, potential, potential[i], i - 1, end_x, end_y);
    if(i%nx_!=nx_-1)    add(costs, potential, potential[i], i + 1, end_x, end_y);
    add(costs, potential, potential[i], i + nx_, end_x, end_y);
    add(costs, potential, potential[i], i - nx_, end_x, end_y);