output_description: For each vertex, print its ID and the distance separated by a space character
  in a line respectively. Print in order of vertex IDs.
input_description: In the first line, an integer $n$ denoting the number of vertices in $G$ is
  given. In the following $n$ lines, adjacency lists for each vertex $u$ are
  respectively given in the following format:
  
  $u$ $k$ $v_1$ $c_1$ $v_2$ $c_2$ ... $v_k$ $c_k$
  
  Vertices in $G$ are named with IDs $0, 1, ..., n-1$. $u$ is ID of the target
  vertex and $k$ denotes its degree. $v_i (i = 1, 2, ... k)$ denote IDs of
  vertices adjacent to $u$ and $c_i$ denotes the weight of a directed edge
  connecting $u$ and $v_i$ (from $u$ to $v_i$).
attempt: import heapq
  import sys
  
  readline = sys.stdin.readline
  
  
  def dijkstra(n):
      inf = 10**6 + 1
      dist = [0] + [inf] * (n - 1)
      q = [(0, 0)]
      while q:
          u = heapq.heappop(q)[1]
          for v, c in edge[u]:
              alt = dist[u] + c
              if dist[v] > alt:
                  dist[v] = alt
                  heapq.heappush(q, (alt, v))
      return dist
  
  
  n = int(input())
  edge = [[]] * n
  for _ in range(n):
      l = list(map(int, readline().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)
  
problem_description: Single Source Shortest Path II
  
  For a given weighted graph $G = (V, E)$, find the shortest path from a source
  to each vertex. For each vertex $u$, print the total weight of edges on the
  shortest path from vertex $0$ to $u$.
samples: [{"input": "5\n    0 3 2 3 3 1 1 2\n    1 2 0 2 3 4\n    2 3 0 3 3 1 4 1\n    3 4 2 1 0 1 1 4 4 3\n    4 2 2 1 3 3", "output": "0 0\n    1 2\n    2 2\n    3 1\n    4 3"}]