Code
The highlighted line runs next. The pill shows the live values in the running call.
Cost
Work done so far, and how the five solutions compare
The list
Originals on top, copies underneath
The highlighted line runs next. The pill shows the live values in the running call.
Work done so far, and how the five solutions compare
Originals on top, copies underneath
Keyboard: ← → step, Space play or pause. Up to 6 nodes written as [val, random_index] pairs (index 0-based, or null). Java has no defaultdict, so solution 3 uses a small get() helper with computeIfAbsent; C++ uses an equivalent helper. Each copy is drawn under its original.