Compilare: main.cpp:2:173: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] std::ifstream f("sort.in");std::ofstream g("sort.out");int d[5][5],fr[4],v[1005],s,i=1,n,x;void F(int i,int j){x=std::min(d[i][j],d[j][i]);d[i][j]-=x;d[j][i]-=x;s+=x;}main(){f>>n;for(;i<=n;)f>>v[i],fr[v[i++]]++;for(i=1;i<=fr[1];)d[1][v[i++]]++;for(i=fr[1]+1;i<=n-fr[3];)d[2][v[i++]]++;for(i=n-fr[3]+1;i<=n;)d[3][v[i++]]++;F(1,2);F(1,3);F(2,3);g<<s+2*(d[1][2]+d[1][3]);} ^