Compilare: main.cpp: In function 'void dfs(int)': main.cpp:25:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[n].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfst(int, int)': main.cpp:35:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < t[n].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfsv(int, int, int)': main.cpp:47:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[n].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:56:35: 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:57:37: 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); ^ main.cpp:58:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:62:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^