Merge Sort in Go

Published on 17 March 2019 (Updated: 17 March 2019)

Welcome to the Merge Sort in Go page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

package main

import (
    "encoding/json"
    "fmt"
    "os"
    "regexp"
    "strconv"
    "strings"
)

func mergeSort(list []int) []int {
    var doMergeSort func(lst [][]int) [][]int
    doMergeSort = func(lst [][]int) [][]int {
        if len(lst) <= 0 {
            return [][]int{}
        }
        if len(lst) == 1 {
            return lst
        }
        return doMergeSort(append([][]int{merge(lst[0], lst[1])}, doMergeSort(lst[2:])...))
    }
    return doMergeSort(split(list))[0]
}

func split(list []int) (splitList [][]int) {
    for _, i := range list {
        splitList = append(splitList, []int{i})
    }
    return
}

func merge(list1 []int, list2 []int) []int {
    if len(list1) <= 0 {
        return list2
    }
    if len(list2) <= 0 {
        return list1
    }
    if list1[0] < list2[0] {
        return append(list1[:1], merge(list1[1:], list2)...)
    }
    return append(list2[:1], merge(list1, list2[1:])...)
}

func strToSliceInt(strList string) []int {
    list := regexp.MustCompile(", ?").Split(strList, -1)
    if len(list) < 2 {
        exitWithError()
    }
    var nums []int
    for _, num := range list {
        n, err := strconv.Atoi(num)
        if err != nil {
            exitWithError()
        }
        nums = append(nums, n)
    }
    return nums
}

func sliceIntToString(list []int) (out string) {
    bytes, _ := json.Marshal(list)
    out = strings.Replace(string(bytes), ",", ", ", -1)
    out = strings.Trim(out, "[]")
    return
}

func exitWithError() {
    fmt.Println("Usage: please provide a list of at least two integers to sort in the format \"1, 2, 3, 4, 5\"")
    os.Exit(1)
}

func main() {
    if len(os.Args) != 2 {
        exitWithError()
    }

    nums := strToSliceInt(os.Args[1])
    nums = mergeSort(nums)
    fmt.Println(sliceIntToString(nums))
}

Merge Sort in Go was written by:

If you see anything you'd like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of Mar 25 2019 19:45:18. The solution was first committed on Mar 17 2019 18:00:21. As a result, documentation below may be outdated.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

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