One possible implementation of a facebook interview question that requires the developer to take a list of users and attempt to union those records that appear to represent the same user. In the sample data, user rows 0, 2, and 3 are one user and row 1 is another therefore: Given an input of these four rows, the output should consist of only 2 rows

facebooktest.go

package main

import (
	"fmt"
)

type contact struct {
	name  string
	phone string
	email string
}

func main() {

	source := make([]contact, 0, 10)

	source = append(source, contact{"Joe Bloggs", "555451", "joe@aol.com"})
	source = append(source, contact{"Jo Bloggs", "347012", "joe@compuserve.com"})
	source = append(source, contact{"J Bloggs", "555451", "joe@msn.com"})
	source = append(source, contact{"Joeseph Bloggs", "457679", "joe@aol.com"})

	output := make(map[int][]contact)
	matches := make([]int, 0, 10)

	for x, _ := range source {
		for y, _ := range source {

			if !contains(matches, y) {
				if source[y].phone == source[x].phone || source[y].email == source[x].email {
					//fmt.Printf("match: %d - %d %s\n", x, y, source[y].email)
					if slice, exists := output[x]; !exists {
						slice = make([]contact, 0, 10)
						slice = append(slice, source[y])
						output[x] = slice
					} else {
						output[x] = append(output[x], source[y])
					}
					matches = append(matches, y)
				}
			}
		}
	}

	for _, v := range output {
		fmt.Println(v)
	}
}

func contains(values []int, x int) bool {
	for _, v := range values {
		if x == v {
			return true
		}
	}
	return false
}