Method integrate

Math/Subset Sum Problem.cpp:205–209

    return ans;
  }
  poly integrate() const {
    int n = size(); vector<mint> ans(n + 1);
    for(int i = 0; i < size(); i++) ans[i + 1] = coef(i) / (i + 1);
    return ans;
  }
  poly inverse(int n) const {  // 1 / p(x) % x^n, O(nlogn)
    assert(!is_zero()); assert(a[0] != 0);
    poly ans{mint(1) / a[0]};