leetcode

0 #define MOD (int)(1E9 + 7)

1 #define SIZE (int)(1E5 + 1)

2 int pows[SIZE] = {1};

3 static const auto Initialize = [] {

4 ios_base::sync_with_stdio(false), cin.tie(nullptr);

5 for (int i = 1; i < SIZE; ++i)

6 pows[i] = (pows[i - 1] << 1) % MOD;

7 return nullptr;

8 }();

9

10 class Solution {

11 public:

12 int numSubseq(vector<int> &nums, int target) {

13 sort(nums.begin(), nums.end());

14 int n = nums.size(), l = 0, r = n - 1;

15

16 int res = 0;

17 while (l <= r) {

18 if (nums[l] + nums[r] > target)

19 r--;

20 else

21 res = (res + pows[r - l++]) % MOD;

22 }

23 return res;

24 }

25 };