setops.go

package setops

import (
    "cmp"
    "slices"
)

func Union[T cmp.Ordered](s1, s2 []T) []T {
    var r []T
    m := make(map[T]struct{})

    for i := 0; i < len(s1); i++ {
        if _, ok := m[s1[i]]; !ok {
            m[s1[i]] = struct{}{}
        }
    }

    for i := 0; i < len(s2); i++ {
        if _, ok := m[s2[i]]; !ok {
            m[s2[i]] = struct{}{}
        }
    }

    for k := range m {
        r = append(r, k)
    }

    slices.Sort(r)
    return r
}

func Intersect[T comparable](s1, s2 []T) []T {
    var r []T
    m := make(map[T]struct{}, len(s2))

    for i := 0; i < len(s2); i++ {
        m[s2[i]] = struct{}{}
    }

    for i := 0; i < len(s1); i++ {
        if _, ok := m[s1[i]]; ok {
            r = append(r, s1[i])
            delete(m, s1[i])
        }
    }

    return r
}

func Diff[T comparable](s1, s2 []T) []T {
    var r []T
    m := make(map[T]struct{}, len(s2))

    for i := 0; i < len(s2); i++ {
        m[s2[i]] = struct{}{}
    }

    for i := 0; i < len(s1); i++ {
        if _, ok := m[s1[i]]; !ok {
            r = append(r, s1[i])
        }
    }

    return r
}

func SymDiff[T comparable](s1, s2 []T) []T {
    var r []T
    return r
}

func Complement[T comparable](s1, s2 []T) []T {
    var r []T
    return r
}