Improve doublylikedlist IndexOf() by reducing the space complexity from O(n) to O(1)

[ksw2000]

Implement IndexOf() without calling Values().

I also checked the performance by running the benchmark I made. Both practical benchmark results and theoretical analysis show that the new implementation significantly improves runtime performance and memory usage

func benchmarkIndexOf(b *testing.B, list *List[int], size int) {
	for i := 0; i < b.N; i++ {
		for n := 0; n < size/4; n++ {
			list.IndexOf(n / 4)
			list.IndexOf(n / 2)
			list.IndexOf(n/4 + n/2)
			list.IndexOf(n - 1)
		}
	}
}

func BenchmarkDoublyLinkedListIndexOf100(b *testing.B) {
	b.StopTimer()
	size := 100
	list := New[int]()
	for n := 0; n < size; n++ {
		list.Add(n)
	}
	b.StartTimer()
	benchmarkIndexOf(b, list, size)
}

func BenchmarkDoublyLinkedListIndexOf1000(b *testing.B) {
	b.StopTimer()
	size := 1000
	list := New[int]()
	for n := 0; n < size; n++ {
		list.Add(n)
	}
	b.StartTimer()
	benchmarkIndexOf(b, list, size)
}

func BenchmarkDoublyLinkedListIndexOf10000(b *testing.B) {
	b.StopTimer()
	size := 10000
	list := New[int]()
	for n := 0; n < size; n++ {
		list.Add(n)
	}
	b.StartTimer()
	benchmarkIndexOf(b, list, size)
}

goos: linux
goarch: amd64
pkg: github.com/emirpasic/gods/v2/lists/doublylinkedlist
cpu: Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz
                               │     old.txt     │               new.txt               │
                               │     sec/op      │   sec/op     vs base                │
DoublyLinkedListIndexOf100-8      86871.0n ± 34%   584.2n ± 1%  -99.33% (p=0.000 n=10)
DoublyLinkedListIndexOf1000-8     9847.72µ ± 19%   84.66µ ± 0%  -99.14% (p=0.000 n=10)
DoublyLinkedListIndexOf10000-8   1220.851m ± 20%   8.908m ± 1%  -99.27% (p=0.000 n=10)
geomean                             10.15m         76.09µ       -99.25%

                               │   old.txt    │                  new.txt                  │
                               │     B/op     │     B/op      vs base                     │
DoublyLinkedListIndexOf100-8     87.50Ki ± 0%    0.00Ki ± 0%  -100.00% (p=0.000 n=10)
DoublyLinkedListIndexOf1000-8    7.813Mi ± 0%   0.000Mi ± 0%  -100.00% (p=0.000 n=10)
DoublyLinkedListIndexOf10000-8   781.3Mi ± 0%     0.0Mi ± 0%  -100.00% (p=0.000 n=10)
geomean                          8.049Mi                      ?                       ¹ ²
¹ summaries must be >0 to compute geomean
² ratios must be >0 to compute geomean

                               │   old.txt   │                 new.txt                  │
                               │  allocs/op  │  allocs/op   vs base                     │
DoublyLinkedListIndexOf100-8      100.0 ± 0%      0.0 ± 0%  -100.00% (p=0.000 n=10)
DoublyLinkedListIndexOf1000-8    1.000k ± 0%   0.000k ± 0%  -100.00% (p=0.000 n=10)
DoublyLinkedListIndexOf10000-8   10.01k ± 0%    0.00k ± 0%  -100.00% (p=0.000 n=10)
geomean                          1.000k                     ?                       ¹ ²
¹ summaries must be >0 to compute geomean
² ratios must be >0 to compute geomean

[ksw2000]

There is the same issue in singlylinkedlist

[ksw2000]

Hi @emirpasic
Just a friendly reminder about this PR. It's been two weeks since submission, and I believe the changes would be beneficial to this package. Please let me know if there's anything I need to adjust. Thanks!

[ksw2000]

Hi @emirpasic
Just a friendly reminder about this PR. It's been about 6 weeks since submission, and I believe the changes would be beneficial to this package. Please let me know if there's anything I need to adjust. Thanks!