View Compilation Error

In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/cassert:43:0,
                 from 0_0_14815119_1643.cpp:7:
0_0_14815119_1643.cpp: In function 'll solve()':
0_0_14815119_1643.cpp:70:42: error: lvalue required as left operand of assignment
                 assert(rig == now && pre = -1);
                                          ^