Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

func (pq *PQ) Push(x interface{}) {
	*pq = append(*pq, x.(Node))
}

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, d[i])
	}
	wtr.Flush()
}

Python: import sys
readline = sys.stdin.readline
from heapq import heapify, heappush, heappop
INF = float("inf")
def MAIN():
    n = int(input())
    adj = [[]] * n
    for _ in range(0, n):
        U = list(map(int, input().split()))
        adj[U[0]] = zip(U[2::2], U[3::2])
    def dijkstra():
        d = [0] + [INF] * (n - 1)
        hq = [(0, 0)]
        while hq:
            u = heappop(hq)[1]
            for v, c in adj[u]:
                alt = d[u] + c
                if d[v] > alt:
                    d[v] = alt
                    heappush(hq, (alt, v))
        print("\n".join(f"{i} {c}" for i, c in enumerate(d)))
    dijkstra()
MAIN()

Python: import heapq

class Pair:
    def __init__(self, num=None, wei=None):
        self.num = num
        self.wei = wei # weight
    def __str__(self):
        return str(self.num) + ' ' + str(self.wei)

def createAdjList():
    adjList = []
    for i in range(n):
        innerList = []
        u, k, *v = map(int, input().split())
        for j in range(0, k*2, 2):
            # [weight, num] (not [num, weigt])
            # Comparison of lists in Python is lexicographical -  the first non-equal pair determines the winner of the ordering
            newPair = [v[j+1],v[j]]
            innerList.append(newPair)
        adjList.append(innerList)
    return adjList

#TODO: write dijkstra
def dijkstra():
    d[0] = 0
    pq = []
    pq.append([0,0])
    heapq.heapify(pq)

    while len(pq) > 0:
        # cost が最小の node を選択
        uWei, uNum  = heapq.heappop(pq)

        status[uNum] = VISITED

        # uWei が最小コストでない場合は無視 (wight 更新前に push された、最短ではないルート)
        if d[uNum] < uWei:
            continue

        # u と v をつなぐ edge のうち最小の経路のコストの合計に更新
        for v in adjList[uNum]:
            vNum = v[1]
            vWei = v[0]
            if status[vNum] != VISITED and d[uNum] + vWei < d[vNum]:
                d[vNum] = d[uNum] + vWei
                status[vNum] = VISITING
                heapq.heappush(pq, [d[vNum], vNum])

import sys
# sys.stdin = open('input.txt')

n = int(input())
NOT_VISITED = 0 # WHITE
VISITING = 1 # GRAY
VISITED = 2 # BLACK
INFTY = 10**21

status = [NOT_VISITED] * n
d = [INFTY] * n
p = [-1] * n

adjList = createAdjList()
dijkstra()
for i in range(n):
    print(i, d[i])

Python: from heapq import*
I=float("inf")
def m():
 n=int(input())
 A=[]
 for _ in range(n):
  e=list(map(int,input().split()))
  A+=[zip(e[2::2],e[3::2])]
 d=[0]+[I]*n
 H=[(0,0)]
 while H:
  u=heappop(H)[1]
  for v,c in A[u]:
   t=d[u]+c
   if d[v]>t:
    d[v]=t
    heappush(H,(t,v))
 print('\n'.join(f'{i} {d[i]}'for i in range(n)))
m()

Python: import queue

INFTY=1<<21

#ダイクストラ法
def dijkstra(n,EdgeMatrix,start):

    NodeList=queue.PriorityQueue() #探索対象の頂点
    Distance=[INFTY]*n #頂点0からの最短経路
    used=[False]*n #頂点の使用情報

    Distance[start]=0 #0から0までの距離は0
    used[start]=True #0から探索を始める
    LastNode=start #最新の頂点
    count=1 #つないだ頂点の数

    while count<n:
        for i in range(len(EdgeMatrix[LastNode])):
            #探索していない頂点へ距離の短い辺があればキューに追加
            Edge=EdgeMatrix[LastNode][i]
            if used[Edge[0]]==False and Distance[Edge[0]]>Distance[LastNode]+Edge[1]:
                    Distance[Edge[0]]=Distance[LastNode]+Edge[1]
                    NodeList.put([Distance[Edge[0]],Edge[0]])

        #最も近い探索していない頂点
        while True:
            minNode=NodeList.get()
            if used[minNode[1]]==False:
                break

        LastNode=minNode[1] #最新の頂点を更新
        used[minNode[1]]=True #頂点の使用情報を更新
        count+=1 #つないだ頂点の数を更新
    return Distance

#入力
n=int(input())

#辺の隣接行列
EdgeMatrix=[[] for i in range(n)]
for i in range(n):
    l=(list(map(int,input().split())))
    for j in range(l[1]):
        EdgeMatrix[l[0]].append([l[2*j+2],l[2*j+3]])

#頂点0からの最短経路
Distance=dijkstra(n,EdgeMatrix,0)

for node,distance in enumerate(Distance):
    print(node,distance)