Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

C++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_12_B: Single Source Shortest Path I

#include <algorithm>
#include <cstdio>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  const uint INFINIT;
  
public:

  Graph(uint n) : n_(n), g_(new uint[(n_*n_)]), INFINIT(100000*(n_-1)+1) {
    std::fill_n(g_, (n_*n_), INFINIT);
  }

  ~Graph() { delete[] g_; }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  void dijkstra(uint* dist)
  {
    std::fill_n(dist, n_, INFINIT);
    bool visited[n_];
    std::fill_n(visited, n_, false);
    auto i = 0u; // 0-start
    visited[i] = true;
    dist[i] = 0u;
    for (auto n = 0u; n < n_-1; ++n) {
      auto cur_min = INFINIT;
      auto es = (*this)[i];
      auto base_dist = dist[i];
      for (auto j = 0u; j < n_; ++j) {
        if (visited[j]) continue;
        dist[j] = std::min(dist[j], base_dist+es[j]);
        if (cur_min > dist[j]) {
          cur_min = dist[j];
          i = j;
        }
      }
      visited[i] = true;
    }
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

  uint u, k, v, c;
  for (auto i = 0u; i < n; ++i) {
    std::scanf("%u %u", &u, &k);
    for (auto j = 0u; j < k; ++j) {
      std::scanf("%u %u", &v, &c);
      g[u][v] = c;
    }
  }

  uint dist[n];
  g.dijkstra(dist);
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %u\n", i, dist[i]);
  }
}

// eof

C++: #include <bits/stdc++.h>

using namespace std;

int n;
typedef pair<int, int> P;
const int N = 110;
vector<P> G[N];
int dis[N];
bool vis[N];

void dijkstra() {
    memset(vis, false, sizeof(vis));
    for (int i = 0; i < n; i++) dis[i] = INT_MAX;
    priority_queue<P, vector<P>, greater<P>> heap;
    heap.push({0, 0});
    dis[0] = 0;

    while (!heap.empty()) {
        int u = heap.top().second, cost = heap.top().first;
        heap.pop();
        if (vis[u]) continue;
        vis[u] = true;
        for (int i = 0; i < G[u].size(); i++) {
            int v = G[u][i].second, len = G[u][i].first;
            if (!vis[v] && dis[u] + len < dis[v]) {
                dis[v] = dis[u] + len;
                heap.push({dis[v], v});
            }
        }
    }
}

int main() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        int v, c;
        for (int j = 0; j < k; j++) {
            cin >> v >> c;
            G[u].push_back({c, v});
        }
    }

    dijkstra();

    for (int u = 0; u < n; u++) {
        cout << u << " " << dis[u] << endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
#define int long long
#define rng(i, l, r) for (size_t i = (l); i < (r); ++i)
#define rep(i, n) rng(i, 0, n)
#define gnr(i, l, r) for (size_t i = (r)-1; i >= (l); i--)
#define per(i, b) gnr(i, 0, b)
#define ALL(obj) (obj).begin(), (obj).end()    //1,2,3,...
#define rALL(obj) (obj).rbegin(), (obj).rend() //...,3,2,1

using namespace std;

const int INF = 1e18;
struct edge
{
    int to, cost;
};
using Graph = vector<vector<edge>>;

static const int MAX = 10000;

static const int YET = 0;
static const int CHK = 1;
static const int END = 2;

int n;
Graph G;

void dijkstra()
{
    priority_queue<pair<int, int>> pq;
    int seen[MAX];
    int dist[MAX];

    memset(seen, YET, sizeof(seen));
    //memset(dist, INF, sizeof(dist));
    rep(i, MAX) dist[i] = INF;

    dist[0] = 0;
    seen[0] = CHK;
    pq.push(make_pair(0, 0));

    while (!pq.empty())
    {
        auto minDistV = pq.top();
        pq.pop();
        int u = minDistV.second;
        int uc = minDistV.first * (-1);
        seen[u] = END;

        if (dist[u] < uc)
            continue;

        for (auto ne : G[u])
        {
            int nv = ne.to;
            int nvc = ne.cost;

            if (seen[nv] == END)
                continue;
            if (dist[u] + nvc < dist[nv])
            {
                dist[nv] = dist[u] + nvc;
                pq.push(make_pair(dist[nv] * (-1), nv));
                seen[nv] = CHK;
            }
        }
    }

    for (int i = 0; i < n; i++)
    {
        cout << i << " " << ((dist[i] == INF) ? -1 : dist[i]) << endl;
    }
}

void solve()
{

    // remove the bottom 3 lines when you submit this code.
    std::ifstream in("./sample.txt");
    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> n;
    G.resize(n);
    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int vertex, cost;
            cin >> vertex >> cost;
            G[u].push_back((edge){vertex, cost});
        }
    }

    dijkstra();

    return;
}

signed main()
{
    solve();
    return 0;
}