Go: package main

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

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

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

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

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

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

Python: import heapq

INF = 1e9

n = int(input())
adj_list = [[]] * n

for u in range(n):
    U = list(map(int, input().split()[2:]))
    adj_list[u] = zip(U[0::2], U[1::2]) # adj_list[u] = (v, cost)


def dijkstra(x):
    d = [INF] * x
    d[0] = 0
    hq = [(0, 0)] # (distance, v)??????????????¬??????????????????(key, ????´?)???????????????push, pop?????????
    
    while hq:
        u = heapq.heappop(hq)[1]
        for v, c in adj_list[u]:
            if d[v] > d[u] + c:
                d[v] = d[u] + c
                heapq.heappush(hq, (d[u] + c, v))
                
    return d

for i, di in enumerate(dijkstra(n)):
    print(i,di)

Python: import heapq as hp

INF = 1000000

def diikstraMethd(G, s):
    # ?????????
    n = len(G)
    d = [INF for _ in range(n)]
    d[s] = 0
    PQ = [(d[s], s)]

    while PQ:
        u = hp.heappop(PQ)[1]
        for v, c in G[u]:
            alt = d[u] + c
            if d[v] > alt:
                d[v] = alt
                hp.heappush(PQ, (alt, v))

    return d


if __name__ == '__main__':
    n = int(input())
    G = [ [] for _ in range(n)]
    for _ in range(n):
        tmp = list(map(int, input().split()))
        u = tmp.pop(0)
        k = tmp.pop(0)
        for i in range(k):
            v = tmp.pop(0)
            c = tmp.pop(0)
            G[u].append((v, c))

    d = diikstraMethd(G, 0)

    for i in range(n):
        print('{0} {1}'.format(i, d[i]))

Python: from heapq import heapify, heappush, heappop

# input
n = int(input())

nodes = [[] * n for i in range(n)]
for _ in range(n):
    line = list(map(int, input().split()))
    u = line.pop(0)
    k = line.pop(0)
    for i in range(k):
        v = line.pop(0)
        c = line.pop(0)
        nodes[u].append((v, c))


# 変数定義
inf = 100 * 100000 + 1

d = [inf] * n
V = set([i for i in range(n)]) #nodeの一覧
S = set() #探索済みnodeの一覧

# 探索
start = 0
target = start
d[start] = 0

H = []

#for i in range(n):
#    heappush(H, (i, d[i]))
heappush(H, (start, d[start]))

while V != S:
    u, c = heappop(H)
    S.add(u)
    for v, c in nodes[u]:
        if d[u] + c < d[v]:
            d[v] = d[u] + c
            heappush(H, (v, d[v]))
    
# 出力
for i in range(n):
    print(f"{i} {d[i]}")

Python: import heapq
class Edge:
    src=-1
    dest=-1
    cost=-1

def Dijkstra(graph,s):
    INF=int(1e9)
    d=[INF]*len(graph)
    d[s]=0
    used=[False]*len(graph)
    que=[]
    heapq.heappush(que,(0,s))
    while len(que)!=0:
        val=heapq.heappop(que)
        v=val[1]
        if used[v] : continue
        used[v]=True
        for i in range(0,len(graph[v])):
            e=graph[v][i]
            if d[v]+e.cost<d[e.dest]:
                d[e.dest]=d[v]+e.cost
                heapq.heappush(que,(d[e.dest],e.dest))
    return d

V=int(input())
graph=[[] for i in range(0,V)]
for i in range(0,V):
    vals=list(map(int,input().split(" ")))
    k=vals[1]
    for j in range(0,k):
        v=vals[2+j*2]
        c=vals[3+j*2]
        e=Edge()
        e.src=i
        e.dest=v
        e.cost=c
        graph[i].append(e)

d=Dijkstra(graph,0)
for i in range(0,V):
    print(str(i)+" "+str(d[i]))

Python: import sys
readline = sys.stdin.readline
from heapq import heapify, heappush, heappop
INF = float("inf")
def MAIN():
    n = int(input())
    G = [[i, INF] for i in range(n)]
    G[0][1] = 0
    m = {}
    for _ in range(n):
        A = list(map(int, readline().split()))
        m[A[0]] = {}
        for i in range(2, len(A), 2):
            m[A[0]][A[i]] = A[i + 1]
    dp = [(0, 0)]
    while dp:
        cost, u = heappop(dp)
        for v, c in m[u].items():
            if G[v][1] > G[u][1] + c:
                G[v][1] = G[u][1] + c
                heappush(dp, (G[v][1], v))
    print(*G)
MAIN()

Python: from heapq import*
I=float("inf")
def m():
 n=int(input())
 A=[]
 for _ in[0]*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 sys, collections, heapq
input = lambda: sys.stdin.readline().rstrip() 
sys.setrecursionlimit(10**7)
INF = 10**10
def I(): return int(input())
def F(): return float(input())
def SS(): return input()
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LSS(): return input().split()

def dijkstra(G, s):
    que = []
    d = [INF]*len(G)
    d[s] = 0
    heapq.heappush(que, (d[s], s))

    while que:
        p = heapq.heappop(que)
        v = p[1]
        if d[v] < p[0]: continue
        for e in G[v]:
            if d[e[0]] > d[v] + e[1]:
                d[e[0]] = d[v] + e[1]
                heapq.heappush(que, (d[e[0]], e[0]))
    return d

def resolve():
    n = I()
    G = [[] for _ in range(n)]
    for i in range(n):
        ukvc = LI()
        u = ukvc[0]
        k = ukvc[1]
        for j in range(k):
            v = ukvc[2*j+2]
            c = ukvc[2*j+3]
            G[u].append((v, c))

    ans = dijkstra(G, 0)
    for i, e in enumerate(ans):
        print(i, e)

if __name__ == '__main__':
    resolve()