dualfroz
5894b8b560
Heap's Algorithm generates each permutation by swapping two elements of a working array in place, and that working array was the argument itself, so permutationsHeap([1, 2, 3]) left the caller holding [3, 2, 1]. Two calls on one array returned different lists, and a frozen array threw. Copy the input up front and swap on the copy, as shuffle and numericSort already do. The returned permutations are unchanged.
582 B
582 B
simple-statistics
| simple-statistics |
|---|
| patch |
Fix permutationsHeap permuting the caller's array. Heap's Algorithm works by swapping elements in place, and the implementation ran those swaps directly on the argument, so permutationsHeap([1, 2, 3]) left the caller holding [3, 2, 1], the last permutation generated. Calling it twice on the same array returned two different lists, and a frozen input threw TypeError: Cannot assign to read only property '0'. The swaps now run on a copy, matching the defensive copying already used in shuffle. The returned permutations are unchanged.