小杨编写了一个如下的高精度减法函数：
vector<int> highPrecisionSubtract(vector<int> a, vector<int> b) { vector<int> result; int borrow = 0; for (int i = 0; i < a.size(); ++i) { int digitA = a[i]; int digitB = i < b.size() ? b[i] : 0; int diff = digitA - digitB - borrow; if (diff < 0) { diff += 10; borrow = 1; } else { borrow = 0; } result.push_back(diff); } while (result.size() > 1 && result.back() == 0) { result.pop_back(); } return result;}下面说法，正确的是（ ）。