solution.cpp

#include <vector>

class Solution {
 public:
  int minimumSubarrayLength(std::vector<int>& nums, int k) {
    std::size_t l{0}, r{0}, n{nums.size() + 1};

    int ans{nums[0]};
    int bitCounts[33] = {0};
    for (int i{0}; (1 << i) <= nums[0]; ++i) {
      if ((1 << i & nums[0]) == 0) continue;
      ++bitCounts[i];
    }

    while (true) {
      if (ans >= k) {
        if (r - l + 1 < n) n = r - l + 1;
        if (l < r) {
          for (int i{0}; (1 << i) <= nums[l]; ++i) {
            if ((1 << i & nums[l]) == 0) continue;
            if (--bitCounts[i] == 0) ans = ans & ~(1 << i);
          }
          ++l;
          continue;
        }
      }

      if (++r >= nums.size()) break;
      for (int i{0}; (1 << i) <= nums[r]; ++i) {
        if ((1 << i & nums[r]) == 0) continue;
        if (++bitCounts[i] == 1) ans = ans | (1 << i);
      }
    }

    return n <= nums.size() ? n : -1;
  }
};