View Compilation Error

0_0_17720378_8492.cpp: In function 'int main()':
0_0_17720378_8492.cpp:164:9: error: 'f' was not declared in this scope
         f[i][0]=lcp[b[i+1].id];
         ^
0_0_17720378_8492.cpp:168:13: error: 'f' was not declared in this scope
             f[i][j]=(min(f[i][j-1],f[i+(1<<(j-1))][j-1]));
             ^