Compilare: main.cpp: In function 'void bfs()': main.cpp:158:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<dup[u].size(); i++) ~^~~~~~~~~~~~~~ main.cpp:160:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[u].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:177:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("metro.in", "r", stdin); ^ main.cpp:178:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("metro.out", "w", stdout); ^ main.cpp:180:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:182:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ main.cpp:192:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &poz); ^