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: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

WHITE, GRAY, BLACK = 0, 1, 2
D_MAX = int(1e7 + 1)


def generate_adj_matrix(v_info):
    for v_detail in v_info:
        v_index = int(v_detail[0])
        v_adj_length = int(v_detail[1])
        v_adj_list = v_detail[2:]
        # assert len(v_adj_list) == v_adj_length * 2
        for j in range(0, v_adj_length * 2, 2):
            init_adj_matrix[v_index][v_adj_list[j]] = int(v_adj_list[j + 1])

    return init_adj_matrix


def dijkstra_path():
    path_list[0] = 0

    while True:
        min_cost = D_MAX
        current_vertex = None
        for i in range(vertices_num):
            if color[i] is not BLACK and path_list[i] < min_cost:
                min_cost = path_list[i]
                current_vertex = i

        if min_cost == D_MAX:
            break

        color[current_vertex] = BLACK

        for v in range(vertices_num):
            current_v_weight = adj_matrix[current_vertex].get(str(v), -1)
            if current_v_weight < 0:
                continue
            elif color[v] is not BLACK:
                if path_list[current_vertex] + current_v_weight < path_list[v]:
                    path_list[v] = path_list[current_vertex] + current_v_weight
                    parent_list[v] = current_vertex
                    color[v] = GRAY

    return path_list


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    init_vertices_table = list(map(lambda x: x.split(), _input[1:]))
    # assert len(init_vertices_table) == vertices_num

    parent_list, path_list = [-1] * vertices_num, [D_MAX] * vertices_num
    color = [WHITE] * vertices_num
    init_adj_matrix = [{} for _ in range(vertices_num)]
    adj_matrix = generate_adj_matrix(init_vertices_table)
    ans = dijkstra_path()
    for j in range(vertices_num):
        print(j, ans[j])

Python: from heapq import heappop, heappush

def dijkstra1(g, source):
    # O(ElogV)

    n = len(g)
    inf = float("inf") # 高速化のためにはfloat("inf")ではないほうがいい
    dist = [inf] * n
    dist[source] = 0
    q = [(0, source)]

    while q:
        cost, u = heappop(q)
        if dist[u] < cost:
            continue
        for c, v in V[u]:
            if dist[v] > dist[u] + c:
                dist[v] = dist[u] + c
                heappush(q, (dist[v], v))

    return dist

def dijkstra2(g, source):
    n = len(V)
    inf = float("inf") # 高速化のためにはfloat("inf")ではないほうがいい
    used = [False]*n
    dist = [inf]*n
    dist[0] = 0
    
    for _ in range(n):
        c1, u = min([(dist[i], i) for i in range(n) if not used[i]])
        used[u] = True
        for c2, v in V[u]:
            if v==u: continue
            dist[v] = min(dist[v], c1+c2)
    return dist


if __name__ == "__main__":
    n = int(input())
    V = [[] for _ in range(n)]

    for _ in range(n):
        u, k, *vc = map(int, input().split())
        for i in range(0, 2*k, 2):
            v, c = vc[i], vc[i+1]
            V[u].append((c, v))

    d = dijkstra2(V, 0)
    for i, j in enumerate(d):
        print(i, j)

Python: import heapq

def dijkstra(graph, weights, s):
    d = {u: float('inf') for u in graph}
    d[s] = 0
    queue = []
    heapq.heappush(queue, (0, s))
    while queue:
        w, u = heapq.heappop(queue)
        for v in graph[u]:
            d_temp = d[u] + weights[u, v]
            if d[v] > d_temp:
                d[v] = d_temp
                heapq.heappush(queue, (d_temp, v))
    return d

n = int(input())
graph, weights = {}, {}
for _ in range(n):
    line = input().split()
    neighbors = []
    for i in range(0, 2 * int(line[1]), 2):
        neighbors.append(line[2+i])
        weights[line[0], line[2+i]] = int(line[3+i])
    graph[line[0]] = neighbors

d = dijkstra(graph, weights, '0')

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

Python: n=int(input())
M=[[-1]*n for _ in[0]*n]
for _ in[0]*n:
 e=list(map(int,input().split()))
 for i in range(e[1]):k=2*-~i;M[e[0]][e[k]]=e[k+1]
d=[0]+[1e6]*~-n
c=[1]*n
while 1:
 m,u=1e6,-1
 for i in range(n):
  if m>d[i]and c[i]:m,u=d[i],i
 if u<0:break
 c[u]=0
 for v in range(n):
  if c[v]and 1+M[u][v]and d[v]>d[u]+M[u][v]:
   d[v]=d[u]+M[u][v]
for i in range(n):print(i,d[i])

Python: import heapq

n=int(input())
u=[0]*n
k=[0]*n
v=[0]*n
z=[[] for _ in range(n) ]
for i in range(n):
  u[i],k[i],*v[i] = map(int,input().split())
  for j in range(0,len(v[i]),2):
    z[i].append([v[i][j],v[i][j+1]])
d=[float("inf")]*n 
e=[-1] *n #いったことなければ -1


def dijkstra(x):
  e[x]=0 #ブクマ
  d[x]=0
  q= [ (d[x],x) ] 
  
  while len(q)>0:
    #print(d)
    b,a = heapq.heappop(q)
    e[a]=0
    
    if d[a] < b:
      pass
    else:
      to_go = z[a]
      for s,t in to_go:
        if e[s]==0:
          pass
        else:
          if d[s] > d[a]+t :
            d[s] = d[a]+t
            heapq.heappush( q, (d[s],s) )

  
dijkstra(0)
for i in range(n):
  print(i,d[i])