Compilare: user.cpp: In function ‘int main()’: user.cpp:85:28: warning: unused variable ‘b’ [-Wunused-variable] int left,right,m,x,y,a,b,i,j,node,add,maxflow=0,mincost=0; ^ user.cpp:83:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmcm.in","r",stdin); ^ user.cpp:84:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmcm.out","w",stdout); ^ user.cpp:86:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&left,&right,&m); ^ user.cpp:91:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&a); ^