View Compilation Error

0_0_40078269_25484.cpp: In function 'void hs(int)':
0_0_40078269_25484.cpp:19:33: error: 'base' was not declared in this scope
   19 |         hash1[i] = hash1[i-1] * base + s2[i] - 'a' + 1;
      |                                 ^~~~