Compilare: main.cpp: In function 'int main()': main.cpp:69:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a.size();++i) ~^~~~~~~~~ main.cpp:75:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<b.size();++i) ~^~~~~~~~~ main.cpp:87:19: warning: unused variable 'l' [-Wunused-variable] { long long l=hash_a*curr_pow%MOD, r=(hash_b[i+a.size()-1]-(i?hash_b[i-1]:0)+MOD)%MOD; ^ main.cpp:87:42: warning: unused variable 'r' [-Wunused-variable] { long long l=hash_a*curr_pow%MOD, r=(hash_b[i+a.size()-1]-(i?hash_b[i-1]:0)+MOD)%MOD; ^ main.cpp:96:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<pos.size();++i) ~^~~~~~~~~~~