Compilare: main.cpp: In function 'bool bfs()': main.cpp:45:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[u].size(); i++) { ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:100:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graph[u].size(); i++) { ~~^~~~~~~~~~~~~~~~~ main.cpp:134:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < edge.size(); i++) { ~~^~~~~~~~~~~~~ main.cpp:77:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in", "r", stdin); ^ main.cpp:78:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out", "w", stdout); ^ main.cpp:79:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &u, &x); ^ main.cpp:81:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^ main.cpp:84:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^