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: INF = float("inf")
white = 0; gray = 1; black =2

def dijkstra(s):
    # 頂点sをrootに設定
    mindist[s] = 0 

    while True:
        #最短経路木に頂点(最短経路木とつながる最小コストの辺を持つ頂点)を追加
        mincost = INF
        u = -1
        for i in range(n):
            if color[i] != black and mindist[i] < mincost:
                mincost = mindist[i]
                u = i
        if u == -1: break
        color[u] = black
        # 各頂点についてsからの最小コストを更新
        for v in range(n):
            if color[v] == black: continue # 確定済み
            if M[u][v] == INF: continue # 2頂点の間に辺が存在しない
            if mindist[u] + M[u][v] < mindist[v]:
                mindist[v] = mindist[u] + M[u][v]
                color[v] = gray

if __name__ == "__main__":
    n = int(input())
    M = [[INF]*n for _ in range(n)]
    for i in range(n):
        inp = [int(x) for x in input().split()]
        u = inp[0]
        k = inp[1]
        for v,c in zip(inp[2::2],inp[3::2]): M[u][v] = c
    color = [white]*n #各頂点の訪問状態 （white:未訪問 gray:暫定 black:確定）
    mindist = [INF]*n # 始点sからの最小コスト
    dijkstra(0)
    for i in range(n): print("{} {}".format(i,mindist[i]))

Python: N = int(input())
INF = 10**9

M = [[-1 for i in range(N)] for j in range(N)]
for i in range(N):
  u, k, *vs = list(map(int, input().split()))
  for j in range(k):
    v, c = vs[2*j], vs[2*j+1]
    M[u][v] = c

d = [INF for i in range(N)]
d[0] = 0
p = [-1 for i in range(N)]
mst = [False for i in range(N)]

while True:
  min_w = INF
  for i in range(N):
    if not mst[i] and d[i] < min_w:
      min_w = d[i]
      u = i
  if min_w == INF:
    break
  mst[u] = True
  for v in range(N):
    if M[u][v] != -1 and M[u][v] + d[u] < d[v]:
      d[v] = M[u][v] + d[u]
      p[v] = u

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

Python: #!/usr/bin/python3
n = int(input())
inf = 100 * 100000

M = [[inf for i in range(n)] for j in range(n)]

for i in range(n):
    L = list(map(int, input().split()))
    u = L[0]
    k = L[1]
    v = L[2::2]
    c = L[3::2]
    for j in range(k):
        M[u][v[j]] = c[j]

S = set()
V = set(range(n))
S.add(0)
d = [inf for i in range(n)]
d[0] = 0
count = 0
while len(V - S) != 0:
    T = V - S
    nd = [inf for i in range(n)]
    for s in S:
        for m, c in enumerate(M[s]):
            if d[s] + c < nd[m] and m in T:
                nd[m] = d[s] + c

    min_nd = min(nd)
    u = nd.index(min_nd)
    S.add(u)
    d[u] = min_nd


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

Python: INFTY = 1 << 21
WHITE = 0
GRAY = 1
BLACK = 2
 
n = int(input())
M = [list(map(int, input().split())) for i in range(n)]
 
d = [INFTY for i in range(n)]
color = [WHITE for i in range(n)]
 
for u in range(n):
    U = list(map(int, input().split()[2:]))
    for j in range(0, len(U), 2):
        M[u][U[j]] = U[j + 1]
        
def dijkstra():
    global M, d, color
    d[0] = 0
    color[0] = GRAY
    while(1):
        minv = INFTY
        u = -1
        for i in range(n):
            if (minv > d[i] and color[i] != BLACK):
                u = i
                minv = d[i]
        if (u == -1):
            break
        color[u] = BLACK
        for v in range(n):
            if (color[v] != BLACK and M[u][v] != INFTY):
                if (d[v] > d[u] + M[u][v]):
                    d[v] = d[u] + M[u][v]
                    color[v] = GRAY
    for i in range(n):
        print(str(i), (-1 if d[i] == INFTY else str(d[i])))
dijkstra()

Python: def V_dijkstra(V,AL,S):
    INF=float('inf')
    ans=[INF]*V
    ans[S]=0
    used=[0]*V # 0:未確定
    used[S]=1
    que=[i for i in range(V)]
    while que:
        u=min(que,key=lambda x: ans[x])
        que.pop(que.index(u))
        used[u]=1
        for v,w in AL[u]:
            if not used[v] and ans[v]>ans[u]+w:
                ans[v]=ans[u]+w
    return ans

# verified: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_12_B
N=int(input())
AL=[[] for _ in range(N)]
for _ in range(N):
    for i,x in enumerate(input().split()):
        x=int(x)
        if i==0:
            j=x
        elif i==1:
            pass
        else:
            if i%2==0:
                tmp=[x]
            else:
                tmp.append(x)
                AL[j].append(tmp)
for ans in enumerate(V_dijkstra(N,AL,0)):
    print(*ans)

Python: def main():
    N = int(input())
    G = [[] for _ in range(N)]
    for _ in range(N):
        u, k, *vc = (int(i) for i in input().split())
        for i in range(0, len(vc), 2):
            G[u].append((vc[i], vc[i+1]))
    d = [[(1 << 63)-1, i] for i in range(N)]
    from heapq import heapify, heappop, heappush

    def dijkstra(s):
        d[s][0] = 0
        que = [(d[s][0], s)]
        heapify(que)
        finished = set()
        while len(finished) < N:
            u = heappop(que)
            while u[1] in finished:
                u = heappop(que)
            for v, c in G[u[1]]:
                if v in finished:
                    continue
                if d[v][0] > u[0] + c:
                    d[v][0] = u[0] + c
                    heappush(que, (d[v][0], v))
            finished.add(u[1])
    dijkstra(0)
    for i, val in enumerate(d):
        print(i, val[0])


if __name__ == '__main__':
    main()