Minimum Spanning Tree in Go

Minimum Spanning

Tree in Go

Welcome to the Minimum Spanning Tree 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 (
	"fmt"
	"math"
	"os"
	"strconv"
	"strings"
)

const usage = `Usage: please provide a comma-separated list of integers`

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

	matrix, errM := parseList(os.Args[1])

	if errM != nil {
		printUsage()
	}

	nFloat := math.Sqrt(float64(len(matrix)))
	n := int(nFloat)
	if nFloat != float64(n) || n == 0 {
		printUsage()
	}

	cost, ok := primMST(matrix, n)
	if !ok {
		printUsage()
	}

	fmt.Println(cost)
}

func primMST(matrix []int, n int) (int, bool) {
	if n == 0 {
		return 0, true
	}

	inMST := make([]bool, n)
	minWeights := make([]int, n)
	for i := range minWeights {
		minWeights[i] = math.MaxInt32
	}

	minWeights[0] = 0
	totalWeight := 0
	nodesInTree := 0

	for i := 0; i < n; i++ {
		u := -1
		minVal := math.MaxInt32

		for v := 0; v < n; v++ {
			if !inMST[v] && minWeights[v] < minVal {
				minVal = minWeights[v]
				u = v
			}
		}

		if u == -1 {
			break
		}

		inMST[u] = true
		totalWeight += minVal
		nodesInTree++

		for v := 0; v < n; v++ {
			weight := matrix[u*n+v]
			if weight > 0 && !inMST[v] && weight < minWeights[v] {
				minWeights[v] = weight
			}
		}
	}

	if nodesInTree != n {
		return 0, false
	}

	return totalWeight, true
}

func parseList(input string) ([]int, error) {
	if strings.TrimSpace(input) == "" {
		return nil, fmt.Errorf("empty input")
	}

	parts := strings.Split(input, ",")
	nums := make([]int, 0, len(parts))
	for _, p := range parts {
		val, err := strconv.Atoi(strings.TrimSpace(p))
		if err != nil {
			return nil, err
		}
		nums = append(nums, val)
	}
	return nums, nil
}

func printUsage() {
	fmt.Println(usage)
	os.Exit(1)
}

Minimum Spanning Tree in Go was written by:

• Ștefan-Iulian Alecu

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

How to Implement the Solution

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How to Run the Solution

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