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;
const int maxn = 1111;
#define INF 0x3f3f3f
int n;
struct qnode				//dis
{
	int v, c;
	qnode(int _v=0,int _c=0):v(_v),c(_c){}
	bool operator < (const qnode &r)const
	{
		return c > r.c;
	}
};
struct Edge
{
	int v,cost;
	Edge(int _v=0,int _cost =0):v(_v),cost(_cost){}
};
vector<Edge> E[maxn];
bool vis[maxn];
int dis[maxn];
void Dijkstra(int n, int s)
{
	memset(vis, false, sizeof(vis));
	fill(dis, dis + n, INF);
	priority_queue<qnode> que;			//存dis
	dis[s] = 0;
	que.push(qnode(s, 0));
	qnode temp;
	while (que.size())
	{
		temp = que.top();
		que.pop();
		int u = temp.v;
		if (vis[u])
			continue;
		vis[u] = true;
		for (int i = 0;i < E[u].size();i++)
		{
			int v = E[u][i].v;
			int cost = E[u][i].cost;
			if (!vis[v] && cost + dis[u] < dis[v])
			{
				dis[v] = dis[u] + cost;
				que.push(qnode(v, dis[v]));
			}
		}
	}
}
void addedge(int u, int v, int w)
{
	E[u].push_back(Edge(v, w));
}
int main()
{
	cin >> n;
	for (int i = 0;i < n;i++)
	{
		int a, b, w,k;
		cin >> a >> k;
		for (int j = 0;j < k;j++)
		{
			cin >> b >> w;
			addedge(a, b, w);
		}
	}
	Dijkstra(n,0);
	for (int i = 0;i < n;i++)
	{
		cout<<i<<" "<< dis[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

constexpr int INF = (1 << 30) - 1;
int n;
int dist[105][105];
int d[105];
bool used[105] = {};

void Dijkstra()
{

        fill_n(d, 105, INF);

        d[0] = 0;
        while ( true ) {
                int u = -1;
                for ( int i = 0; i < n; i++ ) {
                        if ( !used[i] && (u == -1 || d[u] > d[i]) ) {
                                u = i;
                        }
                }
                if ( u == -1 ) break;
                used[u] = true;
                for ( int i = 0; i < n; i++ ) {
                        d[i] = min(d[i], d[u] + dist[u][i]);
                }
        }
}

int main()
{
        fill_n(*dist, 105 * 105, INF);
        cin >> 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;
                        dist[u][v] = min(dist[u][v], c);
                }
        }
        Dijkstra();
        for ( int i = 0; i < n; i++ ) {
                cout << i << " " << d[i] << endl;
        }

        return (0);
}

C++: #include <iostream>
#include <queue>
#include <utility>
#include <vector>

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

struct Node {
  std::vector<Edge> ongoingEdges;
  void addEdge(Edge edge) {
    ongoingEdges.push_back(edge);
  }
};

class Graph {
private:
  std::vector<Node> nodes;
  int size;
public:
  Graph(int size): size(size) {
    nodes.resize(size);
  }
  void addEdge(Edge edge) {
    nodes[edge.from].addEdge(edge);
  }

  std::vector<int> calculateDist(int source) {
    std::vector<int> dist(size, (1 << 30));
    std::priority_queue< std::pair<int, int>, std::vector< std::pair<int, int> >, std::greater< std::pair<int, int> > > pq;

    pq.push(std::make_pair(0, source));
    dist[source] = 0;

    while(!pq.empty()) {
      int from = pq.top().second;
      pq.pop();

      for(Edge edge: nodes[from].ongoingEdges) {
        if(dist[edge.to] > dist[from] + edge.weight) {
          dist[edge.to] = dist[from] + edge.weight;
          pq.push({dist[edge.to], edge.to});
        }
      }

    }

    return dist;
  }
};

int main() {
  int n;
  std::cin >> n;
  Graph graph(n);

  for(int i = 0; i < n; i++) {
    int u, k;
    std::cin >> u >> k;

    for(int i = 0; i < k; i++) {
      int v, c;
      std::cin >> v >> c;
      graph.addEdge(Edge(u, v, c));
    }

  }

  std::vector<int> dist = graph.calculateDist(0);

  for(int i = 0; i < n; i++) {
    std::cout << i + 1 << ' ' << dist[i] << std::endl;
  }

}

C++: #include<iostream>
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF 1000000
#define BLACK 2
#define GRAY 1
#define WHITE 0
using namespace std;

int Node[100][100];
int Cost[100];

void dijkstra()
{
	int Color[100];
	REP(i, 100)Color[i] = WHITE;
	REP(i, 100)Cost[i] = INF;

	Color[0] = GRAY;
	Cost[0] = 0;

	while (true)
	{
		int min_index = -1;
		int min_value = INF;
		REP(i, 100)
		{
			if (Color[i] != BLACK && min_value>Cost[i])
			{
				min_value = Cost[i];
				min_index = i;
			}
		}
		if (min_index == -1)break;

		REP(i, 100)
		{
			if (Color[i] != BLACK && i != min_index && Node[min_index][i]!=INF && Node[min_index][i]+min_value<Cost[i])
			{
				Cost[i] = min_value+Node[min_index][i];
				Color[i] = GRAY;
			}
		}
		Color[min_index] = BLACK;
	}
}

int main()
{
	REP(i,100)
	{
		REP(j, 100)
		{
			Node[i][j] = INF;
		}
	}
	REP(i, 100)Node[i][i] = 0;
	int n;
	cin >> n;
	REP(i,n)
	{
		int u, k;
		cin >> u >> k;
		REP(j,k)
		{
			int v, c;
			cin >> v >> c;
			Node[u][v] = c;
		}
	}
	dijkstra();
	REP(i, n)
	{
		cout << i << " " << Cost[i] << endl;
	}

	return 0;
}