chore: move from tools/dsa

Moved the implementation of this hash table from `tools/dsa` #1.

compare.go

@@ -0,0 +1,17 @@
+package cuckoo
+
+// An EqualFunc determines whethers two keys are 'equal'. Keys that are 'equal'
+// are teated as the same by the [Table]. A good EqualFunc is pure,
+// deterministic, and fast. By default, [NewTable] uses [DefaultEqualFunc].
+//
+// This function MUST NOT return true if the [Hash] digest of two keys
+// are different: the [Table] will not work.
+type EqualFunc[K any] = func(a, b K) bool
+
+// DefaultEqualFunc compares two keys by strict equality. Returns true if the
+// keys have [equal values].
+//
+// [equal values]: https://go.dev/ref/spec#Comparison_operators
+func DefaultEqualFunc[K comparable](a, b K) bool {
+	return a == b
+}