Compilare: main.cpp:2:82: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] int x[]={-1,0,1,0},l[1<<15],c[1<<15],a[177][177],b,d,o,q,n,m,k,i,j,v,p,u,*P;main(){std::ifstream f{"alee.in"};for(f>>n>>m;m--;)f>>i>>k,a[i][k]=-1;f>>b>>d>>o>>q;for(i=0;i++<n;)*a[i]=a[i][n+1]=a[0][i]=a[n+1][i]=-1;for(a[b][d]=1,l[p]=b,c[p]=d;p<=u&!a[o][q];)for(j=l[p],v=c[p++],k=-1;k++<3;){P=&a[j+x[k]][v+x[3-k]];if(!*P)*P=a[j][v]+1,l[++u]=j+x[k],c[u]=v+x[3-k];}std::ofstream{"alee.out"}<<a[o][q];} ^ main.cpp: In function 'int main()': main.cpp:2:242: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses] int x[]={-1,0,1,0},l[1<<15],c[1<<15],a[177][177],b,d,o,q,n,m,k,i,j,v,p,u,*P;main(){std::ifstream f{"alee.in"};for(f>>n>>m;m--;)f>>i>>k,a[i][k]=-1;f>>b>>d>>o>>q;for(i=0;i++<n;)*a[i]=a[i][n+1]=a[0][i]=a[n+1][i]=-1;for(a[b][d]=1,l[p]=b,c[p]=d;p<=u&!a[o][q];)for(j=l[p],v=c[p++],k=-1;k++<3;){P=&a[j+x[k]][v+x[3-k]];if(!*P)*P=a[j][v]+1,l[++u]=j+x[k],c[u]=v+x[3-k];}std::ofstream{"alee.out"}<<a[o][q];} ~^~~