Try this test:
9 6
2 3 2 5 3 4 1 6 1

Answer:
8
1 6 1 2 2 5 3 4 3

sort, read from head and tail\
if head+tail>maximum -> add head,tail to the answers (in front),\
otherwise, add head to answers (to the back)\
wow! interesting observation though

Thanks!!!

plz help

The answer of simple test not one, right this answer too:

6 6
1 2 3 3 4 5
5
2 5 3 4 3 1

It's hepled me.

Sorry, for bad English.

Some tests:
6 6
1 2 3 4 5 6
6
1 6 2 5 3 4


6 3
1 2 3 2 1 1
5
1 3 2 2 1 1


10 10
6 3 4 5 2 10 10 5 4 1
8
1 10 2 10 5 6 5 4 4 3


1 6
6
1
6


2 3
3 3
2
3 3


3 3
2 2 1
2
2 2 1


3 3
2 3 2
3
2 3 2


3 3
2 2 3
3
2 3 2


3 3
1 1 3
3
1 3 1


6 6
5 5 5 1 1 1
4
5 5 5 1 1 1


6 7
6 6 6 2 2 2
6
2 6 2 6 2 6


6 8
6 6 6 2 2 2
4
6 6 6 2 2 2

Edited by author 10.07.2014 03:47

I have WA on test#10.

Please some body tell me why i am gettig wrong answer in this. My code is:

#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <algorithm>
#include <string>
#include <cstring>
#include <string.h>
#include <cstdlib>
#include <sstream>
#include <stack>
#include <queue>
#include <numeric>
#include <utility>
#include <cctype>
#include <list>
#include <climits>
#include <signal.h>
#include <ctime>
#include <map>
#include <set>

using namespace std;
#define ll long long int
ll i, j, k, ct=0, m, n, t, x, y, z, tc, a[200000],s;
    vector<ll> ans;
int main(){

    cin >> n >> s;

    for(i = 0; i < n; i++){
        cin >> a[i];
    }

    sort(a,a+n);

    for ( i = n-1; i > 0 ; i-- ) {
        if ( a[i] + a[i-1] <= s ) {
            break;
        }
    }

    //    cout << x << " " << y << endl;
    if(s%2==0){
        x = i+1;
        y = i;
        //z = n-1;
        while ( x < n && y >= 0 ) {

            ans.push_back( a[y] );
            ans.push_back( a[x] );

            x++;
            y--;
        }

        while ( x < n ) {
            ans.push_back( a[x] );
            x++;
        }


        while ( y >= 0 ) {
            ans.push_back( a[y] );
            y--;
        }
    }
    else {
        y = i;

        while ( i < n && a[i] == a[y]){
            ans.push_back( a[i] );
            i++;
        }
        y--;
        x = i;
        while (  x < n && y >= 0 ) {

            ans.push_back( a[x] );
            ans.push_back( a[y] );

            x++;
            y--;
        }
        while ( x < n ) {

            ans.push_back( a[x] );
            x++;
        }

        while ( y >= 0 ) {
            ans.push_back( a[y] );
            y--;
        }
    }


    ct = 0;

    for (  i = 0; i < ans.size(); ) {
        if( i == ans.size() - 1){
            ct++;
            i++;
        }
        else{
            if( ans[i] + ans[i+1] <= s){
                ct++;
                i+=2;
            }
            else{
                ct++;
                i++;
            }
        }
    }

    cout << ct << endl;
    for (  i = 0; i < ans.size(); i++) {
        cout << ans[i] << " ";
    }
    return 0;
}

Edited by author 13.10.2012 20:42