#include using namespace std; using ll = long long; class LiChaoTree{ struct Line{ long long a, b; long long get(long long x){return a * x + b; } Line(long long a, long long b) : a(a), b(b) {} }; struct Node { Node *left, *right; Line line; Node(Line line) : left(nullptr), right(nullptr), line(line) {} }; const long long inf = 1ll << 60; const Line inf_line = Line{0, inf}; Node *root; long long lx, rx; Node* _add_line(Node *nd, Line line, long long l, long long r){ if(l == r) return nullptr; if(nd == nullptr) return new Node(line); long long m = (l + r) >> 1; bool left = (line.get(l) <= nd->line.get(l)); bool mid = (line.get(m) <= nd->line.get(m)); bool right = (line.get(r) <= nd->line.get(r)); if(left && right)nd->line = line; if(left == right)return nd; if(mid) std::swap(nd->line, line); if(left != mid){ nd->left = _add_line(nd->left, line, l, m); }else{ nd->right = _add_line(nd->right, line, m, r); } return nd; } Node* _add_segment_line(long long a, long long b, Node *nd, Line line, long long l, long long r) { if(r <= a || b <= l) return nd; if(a <= l && r <= b) return _add_line(nd, line, l, r); if(nd == nullptr) nd = new Node(inf_line); long long m = (l + r) >> 1; nd->left = _add_segment_line(a, b, nd->left, line, l, m); nd->right = _add_segment_line(a, b, nd->right, line, m, r); return nd; } long long query(long long x, long long l, long long r){ Node *nd = root; long long res = inf; while(r > l && nd != nullptr) { long long m = (l + r) >> 1; res = std::min(res, nd->line.get(x)); if(x < m) { r = m; nd = nd->left; } else { l = m; nd = nd->right; } } return res; } public: // [xl, xr) LiChaoTree(long long lx, long long rx) : lx(lx), rx(rx), root(nullptr) {} void add_line(long long a, long long b) { Line line(a, b); root = _add_line(root, line, lx, rx); } void add_segment_line(long long a, long long b, long long l, long long r) { Line line = Line{a, b}; root = _add_segment_line(l, r, root, line, lx, rx); } long long get(long long x) { return query(x, lx, rx); } }; int main(){ ios::sync_with_stdio(false); cin.tie(0); int T; cin >> T; while(T--){ ll X, A; cin >> X >> A; vector dp(A + 1); dp[0] = 0; LiChaoTree LCT(0, A + 1); LCT.add_line(0, 0); for(ll i = 1; i <= A; i++){ dp[i] = LCT.get(i) + i * i + X; LCT.add_line(-2 * i, dp[i] + i * i); } cout << dp[A] << '\n'; } }