Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

type ElementKey int
type Node struct {
	key    ElementKey
	parent *Node
	rank   int
}

func newNode(key ElementKey) *Node {
	node := Node{}
	node.key = key
	node.parent = &node
	node.rank = 0

	return &node
}

func union(x, y *Node) {
	xSet := findSet(x)
	ySet := findSet(y)
	link(xSet, ySet)
}

func link(x, y *Node) {
	if x.rank > y.rank {
		y.parent = x
	} else {
		x.parent = y

		if x.rank == y.rank {
			y.rank++
		}
	}
}

func findSet(x *Node) *Node {
	if x != x.parent {
		x.parent = findSet(x.parent)
	}
	return x.parent
}

func newDisjointSets(nSets int) *DisjointSets {
	sets := DisjointSets{}
	sets.keyToNode = map[ElementKey]*Node{}
	for i := 0; i < nSets; i++ {
		key := ElementKey(i)
		sets.keyToNode[key] = newNode(key)
	}
	return &sets
}

type DisjointSets struct {
	keyToNode map[ElementKey]*Node
}

func (sets *DisjointSets) union(x, y ElementKey) {
	xNode := sets.keyToNode[x]
	yNode := sets.keyToNode[y]
	union(xNode, yNode)
}

func (sets DisjointSets) findSet(x ElementKey) *Node {
	xNode := sets.keyToNode[x]
	return findSet(xNode)
}

type Edge struct {
	i, j   int
	weight int
}

func main() {
	scanner.Split(bufio.ScanWords)

	n := nextInt()
	sets := newDisjointSets(n)
	edges := []Edge{}
	a := make([][]int, n)
	for i := 0; i < n; i++ {
		a[i] = make([]int, n)
		for j := 0; j < n; j++ {
			a[i][j] = nextInt()
			if a[i][j] >= 0 {
				e := Edge{
					i:      i,
					j:      j,
					weight: a[i][j],
				}
				edges = append(edges, e)
			}
		}
	}
	sort.Slice(edges, func(i, j int) bool { return edges[i].weight < edges[j].weight })
	totalWeight := 0
	for _, edge := range edges {
		i := ElementKey(edge.i)
		j := ElementKey(edge.j)
		if sets.findSet(i) != sets.findSet(j) {
			totalWeight += edge.weight
			sets.union(i, j)
		}
	}
	fmt.Println(totalWeight)
}

Python: from enum import Enum


class Mst(object):
    """ minimum spanning tree """
    INFINITY = 999999999
    class Status(Enum):
        """ ?????????????¨??????¶??? """
        white = 1  # ????¨????
        gray = 2  # ?¨???????
        black = 3  #?¨???????

    def __init__(self, data):
        num_of_nodes = len(data)+1
        self.color = [Mst.Status.white] * (num_of_nodes + 1)  # ????????????????¨??????¶???
        self.M = self._make_matrix(data)  # data????????????????????£??\??????
        self.d = [Mst.INFINITY] * num_of_nodes
        self.p = [-1] * num_of_nodes

    def _make_matrix(self, data):
        graph_table = []
        for d in data:
            t = [self.inf_or_num(x) for x in d]
            graph_table.append(t)
        return graph_table

    def inf_or_num(self, n):
        if n == -1:
            return Mst.INFINITY
        else:
            return n

    def prim(self):
        self.d[0] = 0
        self.p[0] = -1

        while True:
            mincost = Mst.INFINITY
            for i in range(len(self.d)-1):
                if self.color[i] != Mst.Status.black and self.d[i] < mincost:
                    mincost = self.d[i]
                    u = i

            if mincost == Mst.INFINITY:
                break

            self.color[u] = Mst.Status.black
            for v in range(len(self.d)-1):
                if self.color[v] != Mst.Status.black and self.M[u][v] != Mst.INFINITY:
                    if self.M[u][v] < self.d[v]:
                        self.d[v] = self.M[u][v]
                        self.p[v] = u
                        self.color[v] = Mst.Status.gray

        results = []
        for i in range(len(self.p)):
            if self.p[i] != -1:
                results.append(self.M[i][self.p[i]])
        return sum(results)



if __name__ == '__main__':
    # ??????????????\???
    n = int(input())
    data = []
    for _ in range(n):
        data.append(list(map(int, input().strip().split(' '))))

    mst = Mst(data)
    print(mst.prim())

Python: n = int(input())
primINF = 2000000000
matrix = []
numV = n
for i in range(n):
    matrix.append(list(map(int, input().split())))

visited = [False] * numV
cost = [primINF] * numV # cost
parent = [-1] * numV # parent node

cost[0] = 0
parent[0] = -1

while True:
    # 訪問済み隣接の最小コストのノードを探索する
    mincost = primINF
    for i in range(n):
        if visited[i] is False and cost[i] < mincost:
            mincost = cost[i]
            u = i
    # 見つからなければ終了する
    if mincost == primINF:
        break
    # 訪問済みにする
    visited[u] = True
    for v in range(n):
        if visited[v] is False and matrix[u][v] != -1:
            if matrix[u][v] < cost[v]:
                cost[v] = matrix[u][v]
                parent[v] = u
res = 0
for i in range(n):
    if parent[i] != -1:
        res += matrix[i][parent[i]]

print(res)

Python: n = int(input())
M = [[float("inf") for i in range(n)] for i in range(n)]
for i in range(n):
 L = list(map(int, input().split()))
 for j,v in enumerate(L):
  if v != -1:
   M[i][j] = v

def prim():
 color = [0] * n
 d = [float("inf")] * n
 p = [-1] * n
 d[0] = 0

 while True:
  minv = float("inf")
  u = -1
  for i in range(n):
   if minv > d[i] and color[i] != 2:
    u = i
    minv = d[i]
  if u == -1: break
  color[u] = 2
  for v in range(n):
   if color[v] != 2 and M[u][v] != float("inf"):
    if d[v] > M[u][v]:
     d[v] = M[u][v]
     p[v] = u
 return sum(d)

print(prim())

Python:  #Treeอสิระท่ีเช่ือมต่อทกุๆVertixในGraph โดยพยายามหาค่าให้มีค่าต่ำที่สุดในการสร้าง

n = int(input()) #รับจำนวน node ทั้งหมด
a = []

for i in range(n):
    inp = input() #รับข้อมูลทั้งหมด
    if "-1" in inp:
        inp = inp.replace("-1","10000") #แทนที่ -1 ด้วย 100000
    a.append(list(map(int, inp.split()))) #splitข้อมูลเป็น int เก็บค่าข้อมูลไว้ใน list

w = 0
v = set()
v.add(0)

while len(v) < n: #วน loop ตามจำนวน n 
    min_w   = 10000 #min weight
    min_idx = 0 #min index
    i = 0
    for node in v:
        if min_w > min(a[node]):
            min_w = min(a[node])
            i = node
            min_idx = a[i].index(min_w)
    if min_idx in v:
        a[i][min_idx] = 10000
        continue
    else:
        w += min_w
        v.add(min_idx)

print(w)

Python: n = int(input())

adj = [list(map(int, input().split())) for i in range(n)]

def mst():
    T = [0]
    gross_weight = 0
    cnt = n - 1
    while cnt:
        ew = 2001
        for i in range(len(T)):
            for tv, tew in enumerate(adj[T[i]]):
                if (tv not in T) and (tew != -1):
                    if tew < ew:
                        v, ew = tv, tew
        T.append(v)
        gross_weight += ew
        cnt -= 1
    print(gross_weight)


mst()

Python: from collections import deque

class Node:
    def __init__(self, val):
        self.val = val
        self.child = []

n = int(input())
g = []
# mst = [[] for _ in range(n)]
# mst = [None for _ in range(n)]

for i in range(n):
    g.append(list(map(int, input().split())))

# print(g)

for i in range(n):
    for j in range(n):
        if g[i][j] == -1:
            g[i][j] = 10**5

mst = Node(0)
# done = set()

def getClosestVertex(done):
    w = 10**10
    closest = None
    for i in done:
        for j in range(len(g[i])):
            if j in done:
                continue
            if g[i][j] < w:
                w = g[i][j]
                closest = j
    return closest, w

done = set()
done.add(0)
ans = 0

while True:
    closest, w = getClosestVertex(done)
    if closest is None:
        break
    else:
        done.add(closest)
        ans += w

print(ans)