Compilare: main.cpp: In function 'void recon(int, int, int)': main.cpp:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < A[layer].size(); ++i) ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:40:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < alpha[ind].size();) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:28:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("cmlsc.in", "r", stdin); ^ main.cpp:29:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("cmlsc.out", "w", stdout); ^ main.cpp:30:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &N, &M); ^ main.cpp:31:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (int i = 0; i < N; ++i) scanf ("%d", &X[i]); ^ main.cpp:32:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (int i = 0; i < M; ++i) scanf ("%d", &Y[i]); ^