Compilare: user.cpp: In function ‘int main()’: user.cpp:48:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[i].size(); ++j) ^ user.cpp:38:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reborn.in", "r", stdin); ^ user.cpp:39:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reborn.out", "w", stdout); ^ user.cpp:40:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &m, &q); ^ user.cpp:43:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &X, &Y); ^ user.cpp:58:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &X, &Y); ^