Team Formation

#include<bits/stdc++.h>

const int Maxn = 1000005;

#define ll long long
using namespace std;
int x[Maxn], pos[33];
int main() {
    int T, N;
    cin >> T;
    while (T--) {
        scanf("%d", &N);
        for (int i = 0; i < N; i++) scanf("%d", &x[i]);
        sort(x, x + N);

        long long ans = 0;
        for (int i = 1; i < N; i++) {
            memset(pos, 0, sizeof(pos));

            int k = x[i], cnt = 0, p = 0; //  cnt -> x[i]二进制中0的个数，p表示0的位置
            while (k) {
                if ((k & 1) == 0) pos[cnt++] = p;
                k >>= 1;
                p++;
            }

            for (int j = 0; j < cnt; j++) {
                int a = 1 << pos[j], b = (1 << (pos[j] + 1)) - 1;
                ans += upper_bound(x, x + i, b) - lower_bound(x, x + i, a);
            }
        }
        printf("%lld
", ans);
    }
}