Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"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
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

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

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

Python: import queue
from sys import maxsize as INFTY
from collections import namedtuple
Q = namedtuple("Q", "u c")

n = int(input())
dic = {}

for _ in range(n):
    a = [int(x) for x in input().split()]
    a.reverse()

    u, k = a.pop(), a.pop()
    for _ in range(k):
        v, c = a.pop(), a.pop()
        dic[(u, v)] = c


def bfs(n, s):
    res = [INFTY] * n
    q = queue.Queue()
    q.put(Q(s, 0))

    while q.qsize() != 0:
        p = q.get()
        if res[p.u] <= p.c: continue
        res[p.u] = p.c

        for i in range(n):
            if i == p.u: continue
            v = (p.u, i)
            if v not in dic: continue
            q.put(Q(i, p.c + dic[v]))
    return res


ans = bfs(n, 0)
for i in range(n):
    print(i, ans[i])

Python: from collections import defaultdict

def dijkstra(G, s):
  heap = Heap()
  heap.push((s, 0))
  fixed = set()
  d = defaultdict(lambda: 999999999999999999999)
  d[s] = 0
  while len(heap.data) > 0:
    v = heap.pop()
    if v in fixed:
      continue
    for u in G[v]:
      if u in fixed:
        continue
      c = G[v][u]
      if d[v] + c < d[u]:
        d[u] = d[v] + c
        heap.push((u, d[u]))
    fixed.add(v)
  return d


class Heap:
  def __init__(self):
    self.data = []

  def push(self,x):
    self.data.append(x)
    i = len(self.data)-1
    while self._p(i) >= 0:
      if self.data[i][1] < self.data[self._p(i)][1]:
        tmp = self.data[i]
        self.data[i] = self.data[self._p(i)]
        self.data[self._p(i)] = tmp
        i = self._p(i)
      else:
        break

  def pop(self):
    ret = self.top()
    n = self.data.pop()
    if len(self.data) > 0:
      self.data[0] = n
      i = 0
      while True:
        if self._l(i) < len(self.data):
          l = self.data[self._l(i)]
        else:
          l = (-1, 999999999999999999999)
        if self._r(i) < len(self.data):
          r = self.data[self._r(i)]
        else:
          r = (-1, 999999999999999999999)
        if l[1] > r[1]:
          if r[1] < self.data[i][1]:
            tmp = self.data[i]
            self.data[i] = self.data[self._r(i)]
            self.data[self._r(i)] = tmp
            i = self._r(i)
          else:
            break
        else:
          if l[1] < self.data[i][1]:
            tmp = self.data[i]
            self.data[i] = self.data[self._l(i)]
            self.data[self._l(i)] = tmp
            i = self._l(i)
          else:
            break
    return ret[0]

  def top(self):
    return self.data[0]

  def _p(self, i):
    i = i+1
    return i//2-1

  def _l(self, i):
    i = i+1
    return i*2-1

  def _r(self, i):
    i = i+1
    return i*2


G = {}

n = int(input())
for _ in range(n):
  entry = [int(v) for v in input().strip().split(' ')]
  u = entry[0]
  k = entry[1]
  G[u] = {}
  for i in range(k):
    v = entry[2+i*2]
    c = entry[3+i*2]
    G[u][v] = c

d = dijkstra(G, 0)

for i in range(n):
  print(i, d[i])

Python: def dijkstra(n, s):
    inf = float('inf')
    color = ['white' for _ in range(n)]
    D = [inf for _ in range(n)]             
    P = [0 for i in range(n)]        
    M = [[inf for _ in range(n)] for _ in range(n)]

    for i in range(n):  
        weight = list(map(int, input().split()))[2:]    
        for j in range(len(weight)//2):
            M[i][weight[2*j]] = weight[2*j+1]   

    D[s] = 0
    P[s] = -1

    while True:
        cost, u = inf, 0
        for i in range(n):
            if color[i] != 'black' and D[i] < cost:  
                cost = D[i]
                u = i
        
        if cost == inf:                         
            break

        color[u] = 'black'                          

        for i in range(n):
            if color[i] != 'black' and M[u][i] != inf:             
                if D[u] + M[u][i] < D[i]:                           
                    D[i] = D[u] + M[u][i]                              
                    color[i] = 'gray'                            
                    P[i] = u                          

    return D

n = int(input())
distance = dijkstra(n, 0)
for i in range(n):
    print(i, distance[i])

Python: n = int(input())
G = [[-1 for i in range(n)] for j in range(n)]
d = [999999 for i in range(n)]
  
for i in range(n):
    v = input().split()
    for j in range(int(v[1])):
        G[int(v[0])][int(v[2+2*j])] = int(v[3+2*j])

flag = [0] * n
tn = [0]
d[0] = 0
for k in range(n):
    for i in range(n):
        if i in tn:
            for j in range(n):
                if G[i][j] != -1:
                    if d[j] > d[i] + G[i][j]:
                        d[j] = d[i] + G[i][j]
                    if j not in tn:
                        tn.append(j)
  
for i in range(n):
    print(str(i) + " " + str(d[i]))