Go: package main

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

const (
	MAX_N      = 10000
	MAX_WEIGHT = 100000
)

type Edge struct {
	start  int
	end    int
	weight int
}

type ShortestInfo struct {
	edges    []Edge
	shortest int
}

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

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	shortestList := make([]ShortestInfo, n)
	for i := 1; i < n; i++ {
		shortestList[i] = ShortestInfo{edges: []Edge{}, shortest: MAX_N*MAX_WEIGHT + 1}
	}

	adjacentMatrix, err := createAdjacentMatrix(n, sc)
	if err != nil {
		panic(err)
	}

	sssp([]int{1}, shortestList, adjacentMatrix)
	for _, v := range shortestList {
		fmt.Printf("%d %d\n", v.getEnd()-1, v.shortest)
	}
}

func (si ShortestInfo) getEnd() int {
	if len(si.edges) == 0 {
		return 1
	} else {
		return si.edges[len(si.edges)-1].end
	}
}

func createAdjacentMatrix(n int, sc *bufio.Scanner) ([][]int, error) {
	adjacentMatrix := make([][]int, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		adjacentMatrix[id] = make([]int, n)
		for j := 0; j < n; j++ {
			adjacentMatrix[id][j] = -1
		}
		vertexNum, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		for j := 0; j < vertexNum; j++ {
			v, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			c, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			adjacentMatrix[id][v] = c
		}
	}
	return adjacentMatrix, nil
}

func sssp(nodeStack []int, shortestList []ShortestInfo, adjacentMatrix [][]int) {
	for len(nodeStack) > 0 {
		currentNode := nodeStack[0]
		nodeStack = nodeStack[1:]
		currentShortest := getShortest(currentNode, shortestList)
		adjacents := findAdjacents(currentNode, adjacentMatrix)
		for i := 0; i < len(adjacents); i++ {
			adj := adjacents[i]
			if currentShortest.shortest+adj.weight < getShortest(adj.end, shortestList).shortest {
				setShortest(adj.end, adj, currentShortest, shortestList)
				nodeStack = append(nodeStack, adj.end)
			}
		}
	}
}

func getShortest(node int, shortestList []ShortestInfo) ShortestInfo {
	return shortestList[node-1]
}

func setShortest(node int, edge Edge, currentShortest ShortestInfo, shortestList []ShortestInfo) {
	newEdges := make([]Edge, len(currentShortest.edges)+1)
	for i := 0; i < len(newEdges)-1; i++ {
		newEdges[i] = currentShortest.edges[i]
	}
	newEdges[len(newEdges)-1] = edge
	shortestInfo := ShortestInfo{edges: newEdges, shortest: currentShortest.shortest + edge.weight}
	shortestList[node-1] = shortestInfo
}

func findAdjacents(currentNode int, adjacentMatrix [][]int) []Edge {
	adjacents := adjacentMatrix[currentNode-1]
	edges := []Edge{}
	for i, v := range adjacents {
		if v > 0 {
			edges = append(edges, Edge{start: currentNode, end: i + 1, weight: v})
		}
	}
	return edges
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

Python: from heapq import*
def m():
 n=int(input())
 A=[[]for _ in[0]*n]
 for _ in[0]*n:
  e=list(map(int,input().split()))
  for i in range(e[1]):k=2*-~i;A[e[0]]+=[(e[k],e[k+1])]
 H=[[0,0]]
 d=[0]+[1e6]*n
 c=[1]*n
 while H:
  f=heappop(H)
  u=f[1]
  c[u]=0
  if d[u]>=f[0]:
   for s in A[u]:
    v=s[0]
    if c[v]and d[v]>d[u]+s[1]:
     d[v]=d[u]+s[1]
     heappush(H,[d[v],v])
 for i in range(n):print(i,d[i])
m()

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

"""
input:
5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3

output:
0 0
1 2
2 2
3 1
4 3
"""

import sys
import heapq as hp

WHITE, GRAY, BLACK = 0, 1, 2
D_MAX = int(5e10 + 1)


def generate_adj_matrix(v_info):
    for each in v_info:
        v_index, v_adj_length, *v_adj_list = map(int, each)
        # assert len(v_adj_list) == v_adj_length * 2
        for pair in zip(v_adj_list[::2], v_adj_list[1::2]):
            init_adj_matrix[v_index][pair[0]] = pair[1]

    return init_adj_matrix


def dijkstra_path():
    # path search init
    path_list[init_vertex_index] = 0
    path_heap = []
    # heapq: rank by tuple[0], here ranked by d[u]
    hp.heappush(path_heap, (0, init_vertex_index))
    while len(path_heap) >= 1:
        current_vertex_index = hp.heappop(path_heap)[1]

        color[current_vertex_index] = BLACK

        current_vertex_index_info = adj_table[current_vertex_index]
        for adj_vertex_index in current_vertex_index_info.keys():
            current_adj_weight = current_vertex_index_info.get(adj_vertex_index)
            if color[adj_vertex_index] is not BLACK:
                # alt: d[u] + w[u,v]
                alt_path = path_list[current_vertex_index] + current_adj_weight
                if alt_path < path_list[adj_vertex_index]:
                    # update path_list
                    path_list[adj_vertex_index] = alt_path
                    # update heap
                    hp.heappush(path_heap, (alt_path, adj_vertex_index))
                    parent_list[adj_vertex_index] = current_vertex_index
                    color[adj_vertex_index] = GRAY

    return path_list


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    init_vertices_table = 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 = tuple(dict() for _ in range(vertices_num))
    init_vertex_index = 0

    adj_table = generate_adj_matrix(init_vertices_table)
    ans = dijkstra_path()
    for i, v in enumerate(ans):
        print(i, v)

Python: import sys
from heapq import*
e=sys.stdin.readline
n=int(e())
A=[[]for _ in[0]*n]
for _ in[0]*n:
 b=list(map(int,e().split()))
 for i in range(b[1]):k=2*-~i;A[b[0]]+=[(b[k],b[k+1])]
H=[[0,0]]
d=[0]+[1e6]*n
c=[1]*n
while H:
 f=heappop(H)
 u=f[1]
 c[u]=0
 if d[u]>=f[0]:
  for s in A[u]:
   v=s[0]
   if c[v]and d[v]>d[u]+s[1]:
    d[v]=d[u]+s[1]
    heappush(H,[d[v],v])
for i in range(n):print(i,d[i])

Python: import heapq
from collections import defaultdict

n = int(input())
graph = defaultdict(list)
for _ in range(n):
    u, k, *edges = map(int, input().split())
    for i in range(0, len(edges), 2):
        graph[u].append((edges[i], edges[i+1]))

q = [(0, 0)]
d = {}

# O(V^2)
while q:
    d_min, u = heapq.heappop(q)
    if u in d:
        continue
    d[u] = d_min
    for v, w in graph[u]:
        if v not in d:
            heapq.heappush(q, (d_min+w, v))

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

Python: import heapq as pq
inf = float("inf")
n = int(input())
M = [None] * n

for i in range(n):
    L = list(map(int, input().split()))
    M[L[0]] = []
    for j in range(L[1]):
        M[L[0]].append([L[2 * j + 2], L[2 * j + 3]])

def dijkstra(s):
    color = [0] * n
    d = [inf] * n
    d[s] = 0
    H =[]
    pq.heappush(H, [0, s])

    while len(H) != 0:
        u2,u1 = pq.heappop(H)
        color[u1] = 1
        if d[u1] < u2:
            continue
        for v1,v2 in M[u1]:
            if color[v1] == 1: continue
            if d[u1] + v2 < d[v1]:
                d[v1] = d[u1] + v2
                pq.heappush(H, [d[v1], v1])
    return d

d = dijkstra(0)
for i,v in enumerate(d):
 print("{} {}".format(i,v))