View Compilation Error

0_0_2190969_32640.cpp: In function `void init()':
0_0_2190969_32640.cpp:23: error: `n' undeclared (first use this function)
0_0_2190969_32640.cpp:23: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2190969_32640.cpp:23: error: `m' undeclared (first use this function)
0_0_2190969_32640.cpp: In function `int solve()':
0_0_2190969_32640.cpp:60: error: return-statement with no value, in function returning 'int'
0_0_2190969_32640.cpp:62: error: return-statement with no value, in function returning 'int'