如题，这道题我写了个二分答案，AC了但是不知道原因。

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const ll INF = 1e18;

int k;
ll n, d, e, sum;

ll F() {
  ll l = 1, r = sum;
  while (l < r) {
    ll mid = (l + r) >> 1;
    if (mid * (sum - mid) == n && (mid - 1) * (sum - mid - 1) + 1 == e * d) {
      return mid;
    } else if (mid * (sum - mid) > n) {
      r = mid - 1;
    } else if (mid * (sum - mid) < n) {
      l = mid + 1;
    }
  }
  return (l * (sum - l) != n || (l - 1) * (sum - l - 1) + 1 != e * d ? sum : l);
}

void Solve() {
  cin >> n >> d >> e;
  sum = n - e * d + 2;
  ll ans = F();
  if (ans == sum) {
    cout << "NO\n";
  } else {
    cout << min(ans, sum - ans) << ' ' << max(ans, sum - ans) << '\n';
  }
}

int main() {
  ios::sync_with_stdio(0), cin.tie(0);
  for (cin >> k; k--; Solve()) {
  }
  return 0;
}