1+(-2)+(+3)+(-4)+^+(-2008)+(2009)
=1-2+3-4+^-2008+2009
=(1-2)+(3-4)+^+(2007-2008)+2009
=-1-1-1-1-^-1+2009
=-1004*1+2009
=1005过程写的太乱，请详细。-1-1-1-1例如上太乱多详细啊