the tabs are still not in place. I'll try to explain it by showing a piece of your code as C strings... You have:
"    for (i = 0; i < n; i++) {\n"
"        if (!EQUAL(a[i],b[i]))\n"
"            return -1;\n"
it should look more like
"    for (i = 0; i < n; i++) {\n"
"\tif (!EQUAL(a[i],b[i]))\n"
"\t    return -1;\n"
It's entirely possible that you used the 'tab' key and gedit translate it to spaces for you, I'm not familiar with gedit so I don't know if it does that and if there is an option to change behavior. Emacs and vim can do the right thing (the vim command to apply it to a file would be something like ":%s/[ ]\{8}/\t/g".

Also; lines 141-143 should be collapsed into a single line, "    } else"