View Compilation Error

0_0_14219700_24995.cpp: In function 'int main()':
0_0_14219700_24995.cpp:145:35: error: 'lx' was not declared in this scope
             if(back[k]!=back[k-1])lx=k;
                                   ^
0_0_14219700_24995.cpp:147:17: error: 'rx' was not declared in this scope
                 rx=k;
                 ^
0_0_14219700_24995.cpp:148:24: error: 'lx' was not declared in this scope
                 rep(kk,lx,rx){
                        ^
0_0_14219700_24995.cpp:31:30: note: in definition of macro 'rep'
 #define rep(i,a,b) for(int i=a;i<=b;i++)
                              ^