K - Counting Good Teams 2

#include <bits/stdc++.h>

#define mp make_pair
#define pb push_back
#define fi first
#define se second

using namespace std;

typedef long long ll;
typedef pair<int ,int> ii;
typedef vector<int> vi;

vi nums;
int cnt[1 << 11][1 << 11];

bool cmp(const int &a, const int &b) {
    int pa = __builtin_popcount(a);
    int pb = __builtin_popcount(b);
    if(pa == pb) {
        return a < b;
    }else {
        return pa < pb;
    }
}

int main() {
    ll n, m;
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        int cur;
        cin >> cur;
        nums.pb(cur);
    }
    sort(nums.begin(), nums.end(), cmp);

    int h1 = m/2;
    int h2 = m - h1;
    ll ans = 0;
    for(int i = 0; i < n; i++) {
        int h1bit = 0;
        int h2bit = 0;
        int curn = nums[i];
        ll curans = 0;
        for(int j = 0; j < h1; j++) {
            h1bit *= 2;
            h1bit += curn&1;
            curn = curn >> 1;
        }
        for(int j = 0; j < h2; j++) {
            h2bit *= 2;
            h2bit += curn&1;
            curn = curn >> 1;
        }

        for(int j = h2bit; j; j = ((j - 1)&h2bit)) {
            curans += cnt[h1bit][j];
        }

        curans += cnt[h1bit][0];
        ans += curans;

        int h1bitneg = (~h1bit)&((1 << h1)-1);

        for(int j = h1bitneg; j; j = ((j - 1)&h1bitneg)) {
            cnt[j | h1bit][h2bit]++;
        }
        cnt[h1bit][h2bit]++;
    }
    cout << (n*(n-1))/2 - ans << endl;
    return 0;
}