clear all
data =readlines("Input.txt");
data = char(data)
gridbefore = zeros(width(data),height(data));
grid = zeros(width(data),height(data));
hashPrev = keyHash(0);
hashCur = keyHash(1);
grid(1,1) = bitset(grid(1,1),2);
while hashPrev ~= hashCur
    hashPrev = keyHash(grid);
    [rows, cols] = find(grid-gridbefore);
    gridbefore = grid;
    for i = 1:length(rows)
        row = rows(i);
        col = cols(i);
        if col-1 >= 1
            if bitget(grid(row,col),3)
                if data(row,col-1) == '|'
                    grid(row,col-1) = bitset(grid(row,col-1),4);
                    grid(row,col-1) = bitset(grid(row,col-1),2);
                elseif data(row,col-1) == '\'
                    grid(row,col-1) = bitset(grid(row,col-1),4);
                elseif data(row,col-1) == '/'
                    grid(row,col-1) = bitset(grid(row,col-1),2);
                else
                    grid(row,col-1) = bitset(grid(row,col-1),3);
                end
            end
        end
        if col+1 <= width(grid)
            if bitget(grid(row,col),1)
                if data(row,col+1) == '|'
                    grid(row,col+1) = bitset(grid(row,col+1),2);
                    grid(row,col+1) = bitset(grid(row,col+1),4);
                elseif data(row,col+1) == '\'
                    grid(row,col+1) = bitset(grid(row,col+1),2);
                elseif data(row,col+1) == '/'
                    grid(row,col+1) = bitset(grid(row,col+1),4);
                else
                    grid(row,col+1) = bitset(grid(row,col+1),1);
                end
            end
        end
        if row-1 >= 1
            if bitget(grid(row,col),4)
                if data(row-1,col) == '-'
                    grid(row-1,col) = bitset(grid(row-1,col),3);
                    grid(row-1,col) = bitset(grid(row-1,col),1);
                elseif data(row-1,col) == '\'
                    grid(row-1,col) = bitset(grid(row-1,col),3);
                elseif data(row-1,col) == '/'
                    grid(row-1,col) = bitset(grid(row-1,col),1);
                else
                    grid(row-1,col) = bitset(grid(row-1,col),4);
                end
            end
        end
        if row+1 <= width(grid)
            if bitget(grid(row,col),2)
                if data(row+1,col) == '-'
                    grid(row+1,col) = bitset(grid(row+1,col),1);
                    grid(row+1,col) = bitset(grid(row+1,col),3);
                elseif data(row+1,col) == '\'
                    grid(row+1,col) = bitset(grid(row+1,col),1);
                elseif data(row+1,col) == '/'
                    grid(row+1,col) = bitset(grid(row+1,col),3);
                else
                    grid(row+1,col) = bitset(grid(row+1,col),2);
                end
            end
        end

    end
    hashCur = keyHash(grid);
end
part1 = length(find(grid))