Compilare: user.cpp: In function ‘int main()’: user.cpp:244:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < v.size() ; i ++) ~~^~~~~~~~~~ user.cpp:245:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = i + 1 ; j < v.size() ; j ++) ~~^~~~~~~~~~ user.cpp:252:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i <= v.size() ; i ++) ~~^~~~~~~~~~~ user.cpp:258:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < a.size() ; i ++) ~~^~~~~~~~~~ user.cpp:266:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 1 ; i <= v.size() ; i ++) ~~^~~~~~~~~~~ user.cpp:39:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("colaj.in" , "r" , stdin); ^ user.cpp:40:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("colaj.out" , "w" , stdout); ^ user.cpp:42:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d" , &n , &m , &p); ^ user.cpp:50:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d" , &x1 , &y1 , &x2 , &y2); ^