Go: package main

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

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

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

		out[u] = q[u]
		delete(q, u)
		visited[u] = struct{}{}
	}

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

func top(q map[int]int) int {
	minu := -1
	min := -1
	for u, d := range q {
		if min < 0 || d < min {
			minu = u
			min = d
		}
	}

	return minu
}

Python: from enum import Enum, auto

INFTY = float('inf')

class Color(Enum):
    WHITE = auto()
    GRAY = auto()
    BLACK = auto()

n = int(input())
M = [[-1 for i in range(n)] for i in range(n)]
for i in range(n):
    line = list(map(int, input().split(' ')))
    if line[1] == 0: continue
    for j in range(2, 2+2*line[1], 2):
        M[i][line[j]] = line[j+1]


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

def dijkstra(s):
    global d
    colors = [Color.WHITE for i in range(n)]
    d = [INFTY for i in range(n)]
    d[s] = 0
    p[s] = -1

    while True:
        mincost = INFTY
        for i in range(n):
            if colors[i] != Color.BLACK and d[i] < mincost:
                mincost = d[i]
                u = i

        if mincost == INFTY: break
        colors[u] = Color.BLACK

        for v in range(n):
            if colors[v] != Color.BLACK and M[u][v] != -1:
                if d[u] + M[u][v] < d[v]:
                    d[v] = d[u] + M[u][v]
                    p[v] = u
                    colors[v] = Color.GRAY

dijkstra(0)
for i in range(n):
    print(i, d[i])

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

Python: n = int(input())
INF = float("inf")
edges = [[] for _ in range(n)]
visited = [False]*n
# edges = [[INF for _ in range(n)] for _ in range(n)]
edges = [[] for _ in range(n) for _ in range(n)]
d = [INF]*n
d[0] = 0

for _ in range(n):
    ls = list(map(int, input().split()))
    u = ls[0]
    degrees = ls[1]
    data = ls[2:]
  
    for i in range(degrees):
        v = data[i*2]
        cost = data[i*2+1]
        edges[u].append((v, cost))
        # edges[u][v] = cost

#通常版
# for _ in range(n):
#     dmin = float("inf")
#     for i in range(n):
#         if not visited[i] and d[i] < dmin:
#             dmin = d[i]
#             u = i
#     visited[u] = True
#     for v, c in enumerate(edges[u]):
#         d[v] = min(d[v], d[u] + c)

# for i in range(n):
#     print(i, d[i])
    
#heap版
import heapq

heap = [(0, 0)]
d[0] = 0


while heap:
    du, u = heapq.heappop(heap)
    for v, cost in edges[u]:
        if du + cost < d[v]:
            d[v] = du +  cost
            heapq.heappush(heap, (d[v], v))

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

Python: from heapq import heappop, heappush 


if __name__ == '__main__':
	n = int(input())
	graph = [[-1]*n for i in range(n)]
	for i in range(n):
		node_data = list(map(int, input().split()))
		index = node_data[0]
		edge_num = node_data[1]
		node_list = node_data[2:]
		for i in range(edge_num):
			graph[index][node_list[i * 2]] = node_list[i * 2 + 1]

	cost_map = [-1 for i in range(n)]

	heap_q = []
	heap_q.append((0, 0))

	while len(heap_q) != 0:
		node = heappop(heap_q)
		cost = node[0]
		u = node[1]

		if cost_map[u] != -1:
			continue
		cost_map[u] = cost

		for v in range(n):
			if graph[u][v] != -1:
				heappush(heap_q, (graph[u][v] + cost, v))

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

Python: V=int(input())
inf=10**9
cost=[[inf]*V for _ in range(V)]
for i in range(V):
    l=list(map(int,input().split()))
    for j in range(l[1]):
        v,c=l[2*j+2],l[2*j+3]
        cost[i][v]=c
d=[inf]*V
d[0]=0
used=[0]*V

while True:
    v=-1
    for u in range(V):
        if (not used[u] and (v==-1 or d[u]<d[v])):
            v=u
    if v==-1:
        break
    used[v]=1
    for u in range(V):
        d[u]=min(d[u],d[v]+cost[v][u])

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

Python: import heapq

N = int(input())
A = [[]for i in range(N)]

for i in range(N):
    u, k, *nums = list(map(int,input().split()))
    for j in range(k):
        t = nums[j*2]
        c = nums[j*2+1]
        A[u].append([t, c])

memo = [1E18] * N
memo[0] = 0
qu = []
heapq.heappush(qu,(0,0))
while len(qu) != 0:
    atop = heapq.heappop(qu)
    for ne in A[atop[1]]:
        next_cost = atop[0] + ne[1]
        if(memo[ne[0]] > next_cost):
            memo[ne[0]] = next_cost
            heapq.heappush(qu, (next_cost,ne[0]))
for i in range(N):
    print(i, memo[i])

Python: #!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin, maxint


def main():
    num = int(stdin.readline())

    L = []
    for _ in xrange(num):
        L.append([int(s) for s in stdin.readline().split()])

    weight = [maxint] * num
    weight[0] = 0
    V = set(xrange(1, num))
    index = 0

    while V:
        Li = L[index]
        for i in xrange(Li[1]):
            v = Li[i*2+2]
            if v not in V:
                continue
            c = Li[i*2+3]
            weight[v] = min(weight[v], c + weight[index])

        index = min(V, key=lambda i: weight[i])
        V.remove(index)

    for i, d in enumerate(weight):
        print(i, d)


main()

Python: def dijkstra(n):
    distance_list[0] = 0
    while True:
        min_distance = 10**9
        u = -1
        for i in range(n):
            distance = distance_list[i]
            if flag_list[i] < 2 and distance < min_distance:
                min_distance = distance
                u = i
        if u == -1:
            break
        flag_list[u] = 2
        for v in range(n):
            edge = m_list[u][v]
            if flag_list[v] < 2 and -1 < edge:
                if distance_list[u] + edge < distance_list[v]:
                    distance_list[v] = distance_list[u] + edge
                    p[v] = u
                    flag_list[v] = 1


if __name__ == "__main__":
    n = int(input())
    m_list = [[-1]*n  for _ in range(n)]
    for i in range(n):
        in_list = list(map(int, input().split()))
        adj_num = in_list[1]
        tmp = []
        if adj_num > 0:
            for j in range(adj_num):
                m_list[i][in_list[j*2+2]] = in_list[j*2+3]

    flag_list = [0]*n # 0: 未到達, 1: 処理中, 2: 完了
    distance_list = [10**9]*n
    p = [-1]*n
    dijkstra(n)
    for i, d in enumerate(distance_list):
        print(i, d)