Note that the Go4Expert parser will most likely add spaces to the long strings, as I think it has done with your original post. In this there are no spaces in x or t.
Also I've tweaked some of the code based on the actual length of x, e.g. as it's less than b, ceil(l/b) will be 1.
for (j=1/*ceil(l/b)*/; j>0; j--)
for (i=l; i>0; i--)