Compilare: user.cpp: In function ‘void convex_hull()’: user.cpp:35:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 2; i < p.size(); i++) { ^ user.cpp: In function ‘void dp()’: user.cpp:102:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (r = stk[i] + 1; r < p.size(); r++) ^ user.cpp:106:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (r = stk[i] + 1; r < p.size(); r++) { ^ user.cpp: In function ‘int main()’: user.cpp:128:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("insula2.in", "r", stdin); ^ user.cpp:129:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("insula2.out", "w", stdout); ^ user.cpp:130:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:132:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf", &a, &b); ^