Compilare: main.cpp: In function 'bool strong_connect_visit(int)': main.cpp:48:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] } while (w != v); ~~^~~~ main.cpp: In function 'void assign()': main.cpp:76:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < components.back().size(); ++i) ~~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:79:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (components.back()[i] > n) main.cpp: In function 'void read()': main.cpp:101:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:112:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &src, &dst); ^ main.cpp: In function 'int main()': main.cpp:131:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.in", "r", stdin); ^ main.cpp:132:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.out", "w", stdout); ^