Compilare: main.cpp: In function 'int main()': main.cpp:41:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d%d",&n,&m,&s); ^ main.cpp:43:30: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d",&a,&b); ^ main.cpp: In function 'void bfs(int)': main.cpp:19:9: warning: iteration 100000 invokes undefined behavior [-Waggressive-loop-optimizations] d[i]=-1; ~~~~^~~ main.cpp:18:12: note: within this loop for(i=1;i<=100001;i++) ~^~~~~~~~