Go examples to better understand Big O notation
$ GOMAXPROCS=1 go test . -v -bench=. -benchmem
BenchmarkIsFirstZero10 2000000000 0.37 ns/op 0 B/op 0 allocs/op
BenchmarkIsFirstZero1M 2000000000 0.37 ns/op 0 B/op 0 allocs/op
BenchmarkContains10 200000000 7.25 ns/op 0 B/op 0 allocs/op
BenchmarkContains1M 3000 508857 ns/op 0 B/op 0 allocs/op
BenchmarkContainsDuplicates10 20000000 57.1 ns/op 0 B/op 0 allocs/op
BenchmarkContainsDuplicates1000 3000 564392 ns/op 0 B/op 0 allocs/op
BenchmarkFibonacci10 5000000 320 ns/op 0 B/op 0 allocs/op
BenchmarkFibonacci20 50000 40093 ns/op 0 B/op 0 allocs/op