请问这题可否用链表做？我用STL写了一个版本，复杂度不确定是不是O(n)的，附上代码：

#include <cstdio>
#include <list>
using namespace std;

#define N 10000000
#define M 100000 + 1
typedef long long ll;
#define isdigit(x) (x >= '0' && x <= '9')

int a[N];
int cnt[M];
list<ll> lst;

inline int read()
{
    char c = getchar();
    while (!isdigit(c))
        c = getchar();
    int x = 0;
    while (isdigit(c))
        x = x * 10 + c - '0', c = getchar();
    return x;
}

int main()
{
    int n;
    n = read();
    for (int i = 0; i < n; i++)
        a[i] = read();

    for (int i = 0; i < n; i++)
        cnt[a[i]]++;
    for (int i = 1; i < M; i++)
        while (cnt[i])
            lst.push_back(i), cnt[i]--;

    ll ans = 0;
    list<ll>::iterator last = lst.begin();
    while (lst.size() > 1)
    {
        list<ll>::iterator first = lst.begin();
        list<ll>::iterator second = lst.begin();
        second++;
        ll t = *first + *second;
        ans += t;
        while (t > *last && last != lst.end())
            last++;
        lst.insert(last, t);
        lst.pop_front();
        lst.pop_front();
    }

    printf("%lld\n", ans);

    return 0;
}