fix bugs for Windows compiling

[RongLiu-Leo]

Change "and" to "&&".

Fix a link error due to the usage of “long” type. It is 32-bit long on Windows 64 bit machines while 64 bit long on Linux 64 bit machines. Replace all occurrences of “long” in the code by “int64_t” to get rid of the link error.

May create a branch for Windows. Or test this change on Linux to merge.