Lang:G++
Edit12345678910111213141516171819202122232425262728293031#include <iostream>#include <vector>#include <algorithm>using namespace std;const int mod = 1e9+7;long quick_power(long a, long b) {long ans = 1;while (b) {if (b & 1)ans = (ans * a) % mod;b >>= 1;a = (a * a) % mod;}return ans;}long large_n_power(int n) {return quick_power(2, n % (mod-1));}int SetCounting(vector<int>& arr, int K) {int n = arr.size();sort(arr.begin(), arr.end());long res = 0;for (int i = 0; i < n; ++i) {int k = lower_bound(arr.begin(), arr.end(), K - arr[i]) - arr.begin();k -= (k==n);if (k >= i) {