View Compilation Error

0_0_7203539_6458.cpp: In member function `void DLX::solve()':
0_0_7203539_6458.cpp:81: error: `m' undeclared (first use this function)
0_0_7203539_6458.cpp:81: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7203539_6458.cpp: At global scope:
0_0_7203539_6458.cpp:90: error: `int m' used prior to declaration