Count distinct number of ints from a list of 1 million ints.

README.md

Solution for counting the distinct number of ints from an array of one million ints

main.go

package main

import (
	"log"
	"math/rand"
	"time"
)

// Find the count of distinct ints in a slice.
// Inputs = array of random ints
// Output = count of unique int values.
// I use a map to store the unique int values. It's more efficient
// than a linear lookup of a slice

func main() {
	rand.Seed(time.Now().UnixNano())
	ints := randomArray(10)

	UniqueInts(ints)
}

func UniqueInts(ints []int) {
	// Store the unique int values. Lookups
	// are performed in constant time. I use a map
	// instead of an array which would be a linear algorithm
	unique := make(map[int]struct{})	
	for _, val := range ints {
		if _, ok := unique[val]; !ok {
			// I'm using only the keys of the map to identify 
			// unique int values
			unique[val] = struct{}{}
		}

	}
	
	log.Printf("The number of unique ints is %d out of %d ints\n", len(unique), len(ints))

}

func randomArray(len int) []int {
	a := make([]int, len)
	for i := 0; i <= len-1; i++ {
		a[i] = rand.Intn(len)
	}
	return a
}