Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:24:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graph[u].size(); i++) { ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'void bfs(int, int)': main.cpp:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graph[u].size(); i++) { ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:59:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb2.in", "r", stdin); ^ main.cpp:60:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb2.out", "w", stdout); ^ main.cpp:63:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:68:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &u, &v, &d, &c); ^