Go: package main

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

const R = 100000000

var sc = bufio.NewScanner(os.Stdin)

var n int
var A [101][101]int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func prim() int {
	var u, Minimum, sum int
	var d, p, color [101]int

	for i := 0; i < n; i++ {
		d[i] = R
		p[i] = -1
		color[i] = 0
	}
	d[0] = 0

	for {
		Minimum = R
		u = -1
		for i := 0; i < n; i++ {
			if Minimum > d[i] && color[i] != 2 {
				u = i
				Minimum = d[i]
			}
		}
		if u == -1 {
			break
		}
		color[u] = 2
		for j := 0; j < n; j++ {
			if color[j] != 2 && A[u][j] != R {
				if d[j] > A[u][j] {
					d[j] = A[u][j]
					p[j] = u
					color[j] = 1
				}
			}
		}
	}

	for i := 0; i < n; i++ {
		if p[i] != -1 {
			sum += A[i][p[i]]
		}
	}
	return sum
}
func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()

	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			e := nextInt()
			if e == -1 {
				A[i][j] = R
			} else {
				A[i][j] = e
			}
		}
	}
	fmt.Println(prim())
}

Python: def main():

    N = 100

    n = int(input())
    adj = [[0 for i in range(n)] for j in range(n)]

    for i in range(n):
        tmp = list(map(int, input().split()))
        u = tmp[0]
        u = u -1
        k = tmp[1]
        v = tmp[2:]
        for j in range(k):
            adj[u][v[j]-1] = 1

    for i in range(n):
        for j in range(n):
            print(adj[i][j], end=" ")
        print()
    return 0

if __name__ == "__main__":
    main()

Python: class UnionFind:
  def __init__(self, v):
    # number of vertices
    self.v = v
    # parents of each node
    self.parents = [None] * v
    # heights of each node
    self.height = [None] * v

  def init(self):
    for i in range(self.v):
      self.parents[i] = i
      self.height[i] = 0

  def find(self, p):
    # finds the group containing p and return the position of its leader
    if self.parents[p] != p:
      self.parents[p] = self.find(self.parents[p])
    return self.parents[p]

  def union(self, p, q):
    parent_p = self.find(p)
    parent_q = self.find(q)

    if parent_p == parent_q: return

    if self.height[p] > self.height[q]:
      self.parents[q] = parent_p
    elif self.height[p] < self.height[q]:
      self.parents[p] = parent_q
    else:
      self.parents[parent_q] = parent_p
      self.height[p] += self.height[q]

  def same(self, p, q):
    return self.find(p) == self.find(q)

class Edge:
  def __init__(self, f, to, cost):
    self.f = f
    self.to = to
    self.cost = cost

  def __lt__(self, arg):
    return self.cost < arg.cost

n = int(input())
edges = []
for i in range(n):
  input_array = list(map(int, input().split()))
  for k in range(len(input_array)):
    if input_array[k] != -1:
      edges.append(Edge(i, k, input_array[k]))

union_find = UnionFind(n)
union_find.init()
edges.sort()

min_cost = 0
mst = []
while len(mst) < n-1:
  edge = edges.pop(0)
  if union_find.same(edge.f, edge.to) == False:
    min_cost += edge.cost
    union_find.union(edge.f, edge.to)
    mst.append(edge)

print(min_cost)

Python: # coding: utf-8
import heapq
n=int(input())
cost=[]
used=[False for i in range(n)]
for i in range(n):
    cost.append(list(map(int,input().split())))
q=[]
heapq.heappush(q,(0,0))
ans=0
while len(q):
    c,newv=heapq.heappop(q)
    if used[newv]:
        continue
    used[newv]=True
    ans+=c
    for nxt in range(n):
        if cost[newv][nxt]!=-1 and not used[nxt]:
            heapq.heappush(q,(cost[newv][nxt],nxt))
print(ans)

Python: n = int(input())
G = [list(map(int, input().split())) for _ in range(n)]

color = ['White']*n
d = [10**6]*n # 移動コスト
d[0] = 0 # 0にはコストゼロ
p = [-1]*n # 親ノード
p[0] = -1 # 0には親なし

def prim():
    while True:
        mincost = 10**6
        u = -1
        # 最小コストを選ぶ
        for i in range(n):
            if color[i] != 'Black' and d[i] < mincost:
                mincost = d[i]
                u = i

        # 道がない
        if mincost == 10**6:
            break

        color[u] = 'Black'

        # 未訪問かつ道があるならコスト表を更新
        for v in range(n):
            if color[v] != 'Black' and G[u][v] != -1:
                if G[u][v] < d[v]:
                    d[v] = G[u][v]
                    p[v] = u
                    color[v] = 'Gray'
    return d

print(sum(prim()))

Python: #!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin, maxint


def main():
    num = int(stdin.readline())

    M = []
    for _ in xrange(num):
        M.append([int(s) for s in stdin.readline().split()])

    g = set(xrange(1, num+1))
    index = g.pop()
    h = {index}
    gravity = 0

    while g:
        minimum = maxint
        for j in h:
            mj = M[j-1]
            for i in g:
                if 0 <= mj[i-1] < minimum:
                    index = i
                    minimum = mj[i-1]
        h.add(index)
        g.remove(index)
        gravity += minimum

    print(gravity)


main()

Python: import sys
import heapq

def main():
    n = int(input())
    next = []
    for _ in range(n):
        l = list(map(int, input().split()))
        next.append([(c, i) for i, c in enumerate(l) if c != -1])
    visited = [0] * n
    connection = 0
    q = [(0, 0)]    # (cost, v)
    heapq.heapify(q)
    ans = 0
    while len(q):
        cost, v = heapq.heappop(q)
        if visited[v]:
            continue

        # そのノードと繋げる
        visited[v] = 1
        connection += 1
        ans += cost
        
        # 新たに繋げたノードから行けるところをエンキュー
        for i in next[v]:
            heapq.heappush(q, i)
        
        # 全部のノードが繋がったら終了
        if connection == n:
            break
    print(ans)
    return

if __name__ == '__main__':
    main()

Python: N = 100

n = int(input())
adj = [[0 for i in range(n)] for j in range(n)]

for i in range(n):
    tmp = list(map(int, input().split()))
    u = tmp[0]
    u = u -1
    k = tmp[1]
    v = tmp[2:]
    for j in range(k):
        adj[u][v[j]-1] = 1
        
for i in range(n):
    for j in range(n):
        print(adj[i][j], end=" ")
    print()

Python: N = int(input())
L = []  # input


def prim():
    # 頂点を適当に選ぶ
    s = None
    for i in range(N):
        for j in range(N):
            if L[i][j] != -1:
                s = i
                break
        if s is not None:
            break
    p = {s}
    T = []
    k = 0
    while k < N - 1:
        # 最終のP内で一番短いやつを加える
        len = float("inf")
        lenside = []
        for sg in p:
            for i in range(N):
                isT = False
                for t in T:
                    if (t[0] == sg and t[1] == i) or (t[0] == i and t[1] == sg):
                        # print("ignore")
                        isT = True
                        continue
                if isT is False and i not in p and L[sg][i] != -1 and L[sg][i] < len:
                    len = L[sg][i]
                    lenside = [sg, i]

        p.add(lenside[0])
        p.add(lenside[1])
        T.append(lenside)
        k = k + 1
        #print(p,T,k)
    cnt = 0
    for t in T:
        cnt += L[t[0]][t[1]]
    print(cnt)


for i in range(N):
    L.append(list(map(int, input().split())))
prim()