Compilare: main.cpp: In function 'void Read()': main.cpp:75:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[1].size(); ++i) ~~^~~~~~~~~~~~~ main.cpp: In function 'void Solve()': main.cpp:113:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[X.second].size(); ++j) ~~^~~~~~~~~~~~~~~~~~~~ main.cpp:117:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < aux.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'void read(int&)': main.cpp:31:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^ main.cpp:45:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^ main.cpp: In function 'void Read()': main.cpp:52:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("mine.in", "r", stdin); ^ main.cpp:53:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("mine.out", "w", stdout); ^ main.cpp:55:31: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^