签到题，不用劳什子线段树，用 STL 就行了，但是常数会大一点，可能需要在 I/O 速度上找补一下。

#include <stdio.h>
#include <set>
#include <algorithm>
#include <chrono>
#include <random>
using namespace std;
inline int rd()
{
    int k = 0;
    char c = getchar();
    while (c < '0' || c > '9') c = getchar();
    while (c >= '0' && c <= '9') k = (k << 1) + (k << 3) + (c ^ '0'), c = getchar();
    return k;
}
const int N = 100010;
int n, k;
int a[N];

struct info
{
    pair<int, int> cal, ori;
    bool operator<(const info& o) const { return (cal == o.cal) ? (ori < o.ori) : (cal < o.cal); }
};

set<int> A;
set<info> sum;
inline void remove_A(int x)
{
    if ((A.find(x) != A.begin()) && (A.upper_bound(x) != A.end()))
    {
        set<int>::iterator nxt = A.upper_bound(x), pre = --A.lower_bound(x);
        sum.erase({make_pair(*nxt - x, *nxt + x), make_pair(x, *nxt)});
        sum.erase({make_pair(x - *pre, x + *pre), make_pair(*pre, x)});
        sum.insert({make_pair(*nxt - *pre, *nxt + *pre), make_pair(*pre, *nxt)});
    } 
    else if (A.find(x) != A.begin())
    {
        set<int>::iterator pre = --A.lower_bound(x);
        sum.erase({make_pair(x - *pre, x + *pre), make_pair(*pre, x)});
    }
    else if (A.upper_bound(x) != A.end())
    {
        set<int>::iterator nxt = A.upper_bound(x);
        sum.erase({make_pair(*nxt - x, *nxt + x), make_pair(x, *nxt)});
    }
    A.erase(x);
}
inline void insert_A(int x)
{
    if (A.count(x)) return;
    A.insert(x);
    if ((A.find(x) != A.begin()) && (A.upper_bound(x) != A.end()))
    {
        set<int>::iterator nxt = A.upper_bound(x), pre = --A.lower_bound(x);
        sum.insert({make_pair(*nxt - x, *nxt + x), make_pair(x, *nxt)});
        sum.insert({make_pair(x - *pre, x + *pre), make_pair(*pre, x)});
        sum.erase({make_pair(*nxt - *pre, *nxt + *pre), make_pair(*pre, *nxt)});
    } 
    else if (A.find(x) != A.begin())
    {
        set<int>::iterator pre = --A.lower_bound(x);
        sum.insert({make_pair(x - *pre, x + *pre), make_pair(*pre, x)});
    }
    else if (A.upper_bound(x) != A.end())
    {
        set<int>::iterator nxt = A.upper_bound(x);
        sum.insert({make_pair(*nxt - x, *nxt + x), make_pair(x, *nxt)});
    }
}
int main()
{
    n = rd(), k = rd();
    for (int i = 1; i <= n; ++i) a[i] = rd();
    sort(a + 1, a + n + 1);
    for (int i = 1; i <= n; ++i) A.insert(a[i]);
    for (int i = 1; i < n; ++i) sum.insert({make_pair(a[i + 1] - a[i], a[i + 1] + a[i]), make_pair(a[i], a[i + 1])});

    int loop = 0;
    while (A.size() > 1)
    {
        info tmp = *sum.begin();
        sum.erase(sum.begin()), ++loop;
        remove_A(tmp.ori.first), remove_A(tmp.ori.second);
        int z = (tmp.ori.first + tmp.ori.second) % k;
        insert_A(z);
    }
    printf("%d\n%d", loop, *A.begin());
}