Compilare: main.cpp: In function 'int main()': main.cpp:43:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < E.size () ; ++ i){ ~~^~~~~~~~~~~ main.cpp:32:9: warning: unused variable 'last' [-Wunused-variable] int last = v3 [1] , nrd = 1; ^~~~ main.cpp:19:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("secv.in" , "r" , stdin); ^ main.cpp:20:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("secv.out" , "w" , stdout); ^ main.cpp:22:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d" , &n); ^ main.cpp:24:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d" , &v [i]); ^