Compilare: user.cpp: In function ‘int main()’: user.cpp:67:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < ls[i].size(); j++) ^ user.cpp:53:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.in", "r", stdin); ^ user.cpp:54:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.out", "w", stdout); ^ user.cpp:56:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &m); ^ user.cpp:58:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &x, &y); ^