remove method

bool remove(T value)

Removes value; returns false (and changes nothing) if it was absent. Audited: 2026-06-12 11:26 EDT

Implementation

bool remove(T value) {
  final List<_SkipNode<T>?> update = List<_SkipNode<T>?>.filled(_maxLevel, null);
  final _SkipNode<T>? candidate = _findPredecessors(value, update);
  if (candidate == null || _compare(candidate.value, value) != 0) {
    return false;
  }
  // Unlink at every level the node participates in; stop at the first level
  // where the node is no longer the immediate successor (it was never linked
  // above its own height).
  for (int i = 0; i <= _level; i++) {
    final _SkipNode<T>? pred = update[i];
    if (pred == null || pred.forward[i] != candidate) break;
    pred.forward[i] = candidate.forward[i];
  }
  // Shrink the active level past now-empty top levels.
  while (_level > 0 && _head.forward[_level] == null) {
    _level--;
  }
  _length--;
  return true;
}