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++: #include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;
using P = pair<int, int>;
constexpr ld EPS = 1e-12;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr int MOD = 1e9 + 7;

template <typename T>
void printv(const vector<T> &v)
{
    int sz = v.size();
    for (int i = 0; i < sz; i++)
    {
        cout << v[i] << " \n"[i == sz - 1];
    }
}

struct UnionFind
{
    vector<int> data;
    UnionFind(int size) : data(size, -1) {}
    bool unite(int x, int y)
    {
        x = root(x);
        y = root(y);
        if (x != y)
        {
            if (data[y] < data[x])
                swap(x, y);
            data[x] += data[y];
            data[y] = x;
        }
        return x != y;
    }
    bool find(int x, int y)
    {
        return root(x) == root(y);
    }
    int root(int x)
    {
        return data[x] < 0 ? x : data[x] = root(data[x]);
    }
    int size(int x)
    {
        return -data[root(x)];
    }
};

struct Edge
{
    int from, to, cost;
    Edge(int from, int to, int cost) : from(from), to(to), cost(cost) {}
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

bool operator<(const Edge &e, const Edge &f)
{
    return e.cost > f.cost;
}

vector<int> dijkstra(const Graph &g, int s)
{
    vector<int> d(g.size(), INF);
    d[s] = 0;
    priority_queue<P, vector<P>, greater<P>> que;
    que.push(P(0, s)); // P(dis, pos)
    while (!que.empty())
    {
        int dist = que.top().first;
        int v = que.top().second;
        que.pop();
        if (d[v] < dist)
            continue;
        for (const auto &e : g[v])
        {
            if (d[e.to] <= d[v] + e.cost)
                continue;
            d[e.to] = d[v] + e.cost;
            que.push(P(d[e.to], e.to));
        }
    }
    return d;
}
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    Graph g(n);
    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int v, c;
            cin >> v >> c;
            g[u].push_back(Edge{u, v, c});
        }
    }
    vector<int> res = dijkstra(g, 0);
    for (int i = 0; i < n; i++)
        cout << i << " " << res[i] << endl;
}

C++: #include <iostream>
#include <vector>
#include <queue>
const int inf=1e9;
using namespace std;
int main(){

  int n,now=0,next;
  priority_queue < pair<int,int>, vector<pair<int,int> >, greater<pair<int,int> > > g[100000],a;
  cin>>n;
  for(int i=0,u,k,v,c;i<n&&cin>>u>>k;i++) for(int j=0;j<k&&cin>>v>>c;j++) g[u].push(make_pair(c,v));
  int flag[100]={},c[100]={};
  for(int i=1;i<n;i++) c[i]=inf;
  for(int i=0;i<n;i++){
    int cnt=0;
    for(;!g[now].empty();g[now].pop()) if(!flag[g[now].top().second]){
        c[g[now].top().second]=min(c[g[now].top().second],c[now]+g[now].top().first);
        a.push(make_pair(g[now].top().first,g[now].top().second));
        if(!cnt) next=g[now].top().second;
        cnt++;
      }
    flag[now]=1;
    for(;flag[a.top().second]!=1;) a.pop();
    now=a.top().second;
  }
  for(int i=0;i<n;i++) cout<<i<<" "<<c[i]<<endl;
  return 0;

}

C++: #include<iostream>
using namespace std;
static const int MAX = 1000;
static const int INFTY = (1<<21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[MAX][MAX];

void dijkstra() {
  int minv;
  int d[MAX], color[MAX];

  for ( int i = 0; i < n; i++ ) {
    d[i] = INFTY;
    color[i] = WHITE;
  }

  d[0] = 0;
  color[0] = GRAY;
  while ( 1 ) {
    minv = INFTY;
    int u = -1;
    for ( int i = 0; i < n; i++ )
      if ( minv > d[i] && color[i] != BLACK ) {
        u = i;
        minv = d[i];
      }
    if ( u == -1 ) break;
    color[u] == BLACK;
    for ( int v = 0; v < n; v++ )
      if ( color[v] != BLACK && M[u][v] != INFTY )
        if ( d[v] > d[u] + M[u][v] ) {
          d[v] = d[u] + M[u][v];
          color[v] = GRAY;
        }
  }

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

int main() {
  cin >> n;
  for ( int i = 0; i < n; i++ )
    for ( int j = 0; j < n; j++ )
      M[i][j] = INFTY;

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

  dijkstra();

  return 0;
}