Compilare: user.cpp: In function ‘void Write()’: user.cpp:30:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < Sol[i].size(); ++j) ^ user.cpp: In function ‘void Read()’: user.cpp:69:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("johnie.in", "rt", stdin); ^ user.cpp:70:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("johnie.out", "wt", stdout); ^ user.cpp:72:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:76:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^