Compilare: user.cpp: In function ‘int main()’: user.cpp:57:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i0 = 0; i0 < v.size(); i0++) { ^ user.cpp:60:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i1 = i0 + 1; i1 < v.size(); i1++) { ^ user.cpp:64:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i2 = i1 + 1; i2 < v.size(); i2++) { ^ user.cpp:74:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); i++) { ^ user.cpp:27:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("count.in", "r", stdin); ^ user.cpp:28:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("count.out", "w", stdout); ^ user.cpp:30:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:33:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^