Go: package main

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

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}
func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = i
	pq[j].index = j
}
func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 // for safety
	*pq = old[0 : n-1]
	return item
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# FileName: 	single_source_shortest_path
# CreatedDate:  2020-06-08 21:54:58 +0900
# LastModified: 2020-06-08 22:28:47 +0900
#


import os
import sys
from collections import deque
#import numpy as np
#import pandas as pd


def main():
    n = int(input())
    graph = [[] for _ in range(n)]
    for _ in range(n):
        line = list(map(int,input().split()))
        u,k = line[0],line[1]
        path = line[2:]
        for i in range(0,2*k,2):
            graph[u].append([path[i+1],path[i]])
    
#    print(graph)
    s=0
    distance=[-1]*n
    Q = deque([s])
    distance[0]=0
    

    while Q:
        u = Q.popleft()
        for dis,v in graph[u]:
            if distance[v]==-1:
                distance[v]=distance[u]+dis
                Q.append(v)

            if distance[v]>distance[u]+dis:
                distance[v]=distance[u]+dis
                Q.append(v)
            


    for i,dis in enumerate(distance):
        print(i,dis)


if __name__ == "__main__":
    main()

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))