Compilare: user.cpp: In function ‘int main()’: user.cpp:40:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (S.size() < N + M - 1) ^ user.cpp:28:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("drum6.in", "r", stdin); ^ user.cpp:29:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:31:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", (V[i] + 1)); ^