message: Update constrained-subset-sum.cpp
diff: @@ -11,7 +11,7 @@ public:
  dq.pop_front();
  }
  const auto& curr = nums[i] + (!dq.empty() ? dq.front().second : 0);
  - while (!dq.empty() && dq.back().second < curr) {
  + while (!dq.empty() && dq.back().second <= curr) {
  dq.pop_back();
  }
  if (curr > 0) {
  