Compilare: main.cpp: In function 'int main()': main.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1 ; i < A.size() ; i++) ~~^~~~~~~~~~ main.cpp:23:9: warning: unused variable 'ans' [-Wunused-variable] int ans = 0 , M = A.size(); ^~~ main.cpp:17:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] FastIO , FILES; ^ main.cpp:17:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]