There was an error with data input using StreamTokenizer, so be careful if you are using it.

Edited by author 05.04.2008 21:15

Edited by author 06.04.2008 04:02

Thank you! Scanner() got AC.

int main()
{
    int n;
    cin>>n;
    int i;
    for(i=0;i<n/2;i++)
        cout<<i+1<<" "<<n-i<<" ";
    if(n%2!=0)
        cout<<((int)n/2)+1<<" ";
    cout<<endl;
    cout<<"1 ";
    for(i=3;i<n;i+=2)
        cout<<i<<" ";
    int p=n;
    if(p%2!=0)
    {    p-=1;
        cout<<n<<" "; }
    for(p=p;p>1;p-=2)
        cout<<p<<" ";
    return 0;
}

input1:
1651 1654654564
output1:
1043406233

intput2:
77251 78156464666454
output2:
37919407177871

intput3:
1 999999999999
output3:
537412247190

input4:
101231 1000000000000000000
output4:
391773528202165271

input5:
123456789 987654321
output5:
567000597

input6:
202250020115 3000200002203254
output6:
1339741370499750