OpenCup :: Stage 5 - GP of Two Mountain Systems :: Problem A

#include <algorithm>
#include <cstdio>
#include <memory.h>

using namespace std;

#define fill(a, x) memset (a, x, sizeof(a))

int n, s, a[111111], l, r, ans, rr[111111], cc;
bool w[111111], pp;

int main() {
    scanf("%d %d", &n, &s);
    for (int i = 0; i < n; ++i)
        scanf("%d", a + i);
    sort(a, a + n);
    reverse(a, a + n);
    l = 0;
    r = n - 1;
    ans = 0;
    cc = 0;
    fill(w, 0);
    while (a[l] == s) {
        w[l] = true;
        rr[cc++] = a[l++];
        ++ans;
    }
    while (r > l) {
        while (r > l && a[l] + a[r] <= s) --r;
        if (r == l) break;
        rr[cc++] = a[r];
        w[r] = true;
        rr[cc++] = a[l];
        w[l] = true;
        --r;
        ++l;
        ans += 2;
    }
    pp = false;
    for (int i = 0; i < n; ++i)
        if (!w[i]) {
            rr[cc++] = a[i];
            if (pp) {
                ++ans;
                pp = false;
            } else pp = true;
        }
    ans = 0;
    pp = false;
    for (int i = 0; i < n; ++i) {
        if (pp)
            if (rr[i - 1] + rr[i] > s) ++ans; else {
                ++ans;
                pp = false;
            }
        else pp = true;
    }
    ans += pp;
    printf("%d\n", ans);
    for (int i = 0; i < n; ++i)
        printf("%d ", rr[i]);
    return 0;
}