Go: package main

import (
	"fmt"
	"sort"
)

type Edge struct {
	I int
	J int
	A int
}

func main() {
	var n int
	fmt.Scan(&n)

	g := make([][]int, n)
	edges := make([]Edge, 0, n*(n-1)/2)
	parents := make([]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			fmt.Scan(&g[i][j])
			if g[i][j] >= 0 {
				edges = append(edges, Edge{i, j, g[i][j]})
			}
		}
		parents[i] = i
	}
	sort.SliceStable(edges, func(i, j int) bool { return edges[i].A >= edges[j].A })

	sum := 0
	num := 0
	for len(edges) > 0 && num < n-1 {
		edge := edges[len(edges)-1]
		edges = edges[:len(edges)-1]

		if same(edge.I, edge.J, &parents) {
			continue
		}
		union(edge.I, edge.J, &parents)
		sum += edge.A
		num += 1
	}
	fmt.Println(sum)
}



func root(id int, parents *[]int) int {
	if id == (*parents)[id] {
		return id
	}
	return root((*parents)[id], parents)
}

func union(i, j int, parents *[]int) {
	(*parents)[root(j, parents)] = (*parents)[root(i, parents)]
}

func same(i, j int, parents *[]int) bool {
	return root(i, parents) == root(j, parents)
}

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)

Python: from sys import stdin
INF = 1<<21
WHITE, GRAY, BLACK = 0, 1, 2
n = int(stdin.readline())
M = [[INF] * n for _ in range(n)]
for i in range(0, n):
    for j, e in enumerate(list(map(int, stdin.readline().split()))):
        if e != -1: M[i][j] = e
d = [INF] * n
d[0] = 0
color = [False] * n
def prim():
    while True:
        minv = INF
        u = -1
        for i in range(0, n):
            if minv > d[i] and color[i] != True:
                u = i
                minv = d[i]
        if u == -1: break
        color[u] = True
        for v in range(0, n):
            if color[v] != True and d[v] > M[u][v]:
                d[v] = M[u][v]
    return sum(d)
print(prim())

Python: #coding:utf-8
inf = 1000000
n = int(input())
mtrx = []
for i in range(n):
    nums = list(map(int,input().split()))
    col = []
    for j in range(n):
        if nums[j] == -1:
            col.append(inf)
        else:
            col.append(nums[j])
    mtrx.append(col)

        
d = [inf for i in range(n)]
p = [-1 for i in range(n)]
color = ["white" for i in range(n)]
d[0] = 0
while True:
    mincost = inf
    for i in range(n):
        if color[i] != "black" and d[i] < mincost:
            mincost = d[i]
            u = i
    if mincost == inf:
        break

    color[u] = "black"
    for v in range(n):
        if color[v] != "black" and mtrx[u][v] < inf:
            if mtrx[u][v] < d[v]:
                d[v] = mtrx[u][v]
                p[v] = u
                color[v] = "gray"
print(sum(d))

Python: n = int(input())
sides = []
ws = []
ss = []
for _ in range(n):
    sides.append(list(map(int,input().split())))
for i in range(n):
    for j in range(i+1,n):
        if sides[i][j] >= 0:
            ws.append([sides[i][j],i,j])
rs = [(i) for i in range(n)]
def root(x):
    global rs
    if rs[x] == x:
        return(x)
    else:
        return(root(rs[x]))
ws.sort()
ans = 0
while(len(ws)):
    if root(ws[0][1]) != root(ws[0][2]):
        ans += ws[0][0]
        rs[root(rs[ws[0][2]])] = root(ws[0][1])
        ss.append(ws[0])
    del(ws[0])
print(ans)

Python: import heapq

def make_adj_list(v):
    adj_list = [[-1 for i in range(v)] for j in range(v)]
    return adj_list

def prim(adj_list, v, s):
    # スタートを0とする
    min_d = 0
    heap = []
    used = []
    for i in range(v):
        used.append(False)
    used[s] = True
    for i in range(v):
        if adj_list[s][i] != -1:
            heapq.heappush(heap, (adj_list[s][i], i))
        #　スタートからつなぐことができる辺をheapに入れる

    while len(heap) != 0:
        cost, to = heapq.heappop(heap)
        if used[to]:
            continue
        min_d += cost
        used[to] = True
        for i in range(v):
            if adj_list[to][i] != -1:
                heapq.heappush(heap, (adj_list[to][i], i)) 
            #集合に入れた頂点からつなぐことができる辺をheapに入れる

    return min_d

def main():
    v = int(input())
    adj_list = make_adj_list(v)
    for i in range(v):
        adj_list[i] = [int(j) for j in input().split()]
    min_d = prim(adj_list, v, 0)
    print(min_d)


if __name__ == '__main__':
    main()