nCr Generator

ncr_generator.go

package main

import "fmt"

// GenerateCombinations generates all combinations of choosing k elements from a set of n elements
func GenerateCombinations(n, k int) [][]int {
	combinations := [][]int{}
	helper(n, k, []int{}, &combinations)
	return combinations
}

func helper(n, k int, current []int, combinations *[][]int) {
	if k == 0 {
		*combinations = append(*combinations, current)
		return
	}

	if n == 0 {
		return
	}

	// Exclude current element
	helper(n-1, k, current, combinations)

	// Include current element
	current = append([]int{n}, current...)
	helper(n-1, k-1, append([]int{}, current...), combinations)
}

func main() {
	n := 5
	k := 3
	allCombinations := GenerateCombinations(n, k)
	fmt.Println(allCombinations)
}