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: #coding:utf-8
inf = 1000000
n = int(input())
M = [[inf for i in range(n)] for j in range(n)]
vwMtrx = []
for i in range(n):
    data = list(map(int,input().split()))
    u = data[0]
    k = data[1]
    col = []
    for j in range(0,2*k,2):
        v, w = data[j+2], data[j+3]
        M[u][v] = w
        col.append([v,w])
    vwMtrx.append(col)

def dijkstra(s):
    color = ["white" for i in range(n)]
    d = [inf for i in range(n)]
    p = [-1 for i in range(n)]
    d[s] = 0
    Q = [[s,0]]
    while Q != []:
        u = min(Q, key=lambda x:x[1])
        Q = [List for List in Q if List != u]
        u = u[0]
        color[u] = "black"

        vwList = vwMtrx[u]
        
        for vw in vwList:
            v,w = vw[0],vw[1]
            if color[v] != "black" and M[u][v] != inf:
                if d[u] + M[u][v] < d[v]:
                    d[v] = d[u] + M[u][v]
                    p[v] = u
                    color[v] = "gray"
                    Q.append([v, d[v]])

    return d

dList = dijkstra(0)
for i, d in enumerate(dList):
    print(i,d)

Python: # 単一始点最短経路 Single source shortest path I

INFTY = 2000000000

n = int(input())
M = [[INFTY for i in range(n)] for i in range(n)]
for i in range(n):
    dat = [int(i) for i in input().split()]
    for j in range(1, dat[1] + 1):
        M[dat[0]][dat[2 * j]] = dat[2 * j + 1]

col = [-1 for i in range(n)]
d = [INFTY for i in range(n)]
p = [-1 for i in range(n)]

d[0] = 0

while True:
    mincost = INFTY
    for i in range(n):
        if col[i] != 1 and d[i] < mincost:
            mincost = d[i]
            u = i
    
    if mincost == INFTY:
        break
    
    col[u] = 1
    
    for v in range(n):
        if col[v] != 1 and M[u][v] != -1:
            if d[u] + M[u][v] < d[v]:
                d[v] = d[u] + M[u][v]
                p[v] = u
                col[v] = 0

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

Python: def dijkstra(n):
    inf = 10 ** 6 + 1
    dist = [0] + [inf] * (n - 1)
    visited = [False] * n

    while not all(visited):
        dmin = inf
        for i, (d, v) in enumerate(zip(dist, visited)):
            if dmin > d and not v:
                u = i

        visited[u] = True
        for (v, c) in edge[u]:
            if dist[v] > dist[u] + c:
                dist[v] = dist[u] + c
    return dist

n = int(input())
edge = [[]] * n
for _ in range(n):
    l = list(map(int, input().split()))
    edge[l[0]] = (e for e in zip(l[2::2], l[3::2]))
for i, c in enumerate(dijkstra(n)):
    print(i, c)

Python: #coding:utf-8
def Dijkestra(G,n):
    d=[100000000000]*n
    pi=[None]*n
    d[0]=0
    C=[]
    for i in range(n):
        C.append(i)
    
    while len(C)!=0:
        u=C[0]
        for i in range(1,len(C)):
            if d[u]>d[i]:
                u=C[i]
        C.remove(u)
        for i in range(len(G[u])):
            if G[u][i]==-1:
                continue
            elif d[i]>d[u]+G[u][i]:
                d[i]=d[u]+G[u][i]
                pi[i]=u
                        
    for i in range(n):
        print(i,d[i])
    

if __name__=="__main__":
    n=int(input())
    G=[]
    for i in range(n):
        a=[]
        ele=list(map(int,input().split()))
        k=ele[1]
        t=ele[2:]
        v=c=[]
        for j in range(k):
            v=v+[t[2*j]]
            c=c+[t[2*j+1]]
        for j in range(n):
            if j in v:
                a.append(c[v.index(j)])
            else:
                a.append(-1)
        G.append(a)
    Dijkestra(G,n)

Python: """Shortest Path"""

import sys
import os
import pprint

#fd = os.open('ALDS1_12_B.txt', os.O_RDONLY)
#os.dup2(fd, sys.stdin.fileno())

level = True
def debug(v):
    if level:
        print(v)

n = int(input())
INF = float('inf')
W = [[INF for j in range(n)] for i in range(n)]

for _ in range(n):
    l = list(map(int, input().split()))
    node_index = l[0]
    num = l[1]
    data = l[2:]
    for i in range(num):
        node = data[i*2]
        weight = data[i*2+1]
        W[node_index][node] = weight

d = [INF] * n
visited = [False] * n
parent = [None] * n

# root
d[0] = 0

while True:
    min_dist = INF
    min_index = None
    for i in range(n):
        if not visited[i] and d[i] < min_dist:
            min_dist = d[i]
            min_index = i

    if min_index is None:
        break

    # accept
    visited[min_index] = True

    for i in range(n):
        if not visited[i] and d[i] > d[min_index] + W[min_index][i]:
            d[i] = d[min_index] + W[min_index][i]
            parent[i] = min_index
for i in range(len(d)):
    s = '{} {}'.format(i, d[i])
    print(s)

Python: #coding:utf-8
def Dijkestra(G,n):
    d=[100000000000]*n
    pi=[None]*n
    d[0]=0
    C=[]
    for i in range(n):
        C.append(i)
    
    while len(C)!=0:
        u=C[0]
        for i in range(1,len(C)):
            if d[u]>d[C[i]]:
                u=C[i]
        C.remove(u)
        for i in range(len(G[u])):
            if G[u][i]==-1:
                continue
            elif d[i]>d[u]+G[u][i]:
                d[i]=d[u]+G[u][i]
                pi[i]=u                
    for i in range(n):
        print(i,d[i])
    

if __name__=="__main__":
    n=int(input())
    G=[]
    for i in range(n):
        a=[]
        ele=list(map(int,input().split()))
        k=ele[1]
        t=ele[2:]
        v=c=[]
        for j in range(k):
            v=v+[t[2*j]]
            c=c+[t[2*j+1]]
        for j in range(n):
            if j in v:
                a.append(c[v.index(j)])
            else:
                a.append(-1)
        G.append(a)
    Dijkestra(G,n)