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 <iostream>
using namespace std;
static const int MAX = 100;
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;

}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <queue>
#include <functional>

#define INPUT_FROM_FILE (0) 
#if INPUT_FROM_FILE
#include <fstream>
#endif

typedef std::pair<int, int> P;

class Edge{
public:
	int to;
	int cost;

	Edge(){
		return;
	}
	~Edge(){
		return;
	}
};

int main(int argc, char **argv){
	std::vector<std::vector<Edge> >  G;
	std::vector<long> min_cost;
	std::priority_queue<P, std::vector<P>, std::greater<P> > que;

	int n, u, k, v, c;

#if INPUT_FROM_FILE
	std::ifstream ifs("test.txt");
	//FILE *fp = fopen("test.txt", "r");
#endif

	
#if INPUT_FROM_FILE
	ifs >> n;
#else
	std::cin >> n;
#endif
	G.resize(n);
	min_cost.resize(n, 1000000000) ;

	for(int i = 0; i < n; i++){
#if INPUT_FROM_FILE
		ifs >> u >> k;
#else
		std::cin >> u >> k;
#endif
		for(int j = 0; j < k; j++){
#if INPUT_FROM_FILE
			ifs >> v >> c;
#else
			std::cin >> v >> c;
#endif
			Edge e;
			e.to = v;
			e.cost = c;

			G[u].push_back(e);

		}
	}

	min_cost[0] = 0;
	que.push(P(0, 0));

	while(!que.empty()){
		P p = que.top(); que.pop();
		int v = p.second;

		if(min_cost[v] < p.first){ 
			continue;
		}

		for(int i = 0; i < G[v].size(); i++){
			Edge e = G[v][i];
			if(min_cost[e.to] > min_cost[v] + e.cost){
				min_cost[e.to] = min_cost[v] + e.cost;
				que.push(P(min_cost[e.to], e.to));
			}
		}
	}

	for(int i = 0; i < n; i++){
		std::cout << i << " " << min_cost[i] << std::endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <limits>

using namespace std;
using MatrixGraph = vector<vector<int>>;

const int infinity = numeric_limits<int>::max();
const int no_label = -1;

vector<int> calc_shortest_path(MatrixGraph matrix_graph, int started_label) {
  vector<int> min_costs(matrix_graph.size(), infinity);
  vector<bool> is_visits(matrix_graph.size(), false);

  min_costs[started_label] = 0;

  while(true) {
    int min_cost_adjacency_label = no_label;
    int min_cost_adjacency_weight = infinity;
    for(int i = 0; i < matrix_graph.size(); i++) {
      if(is_visits[i]) {
        continue;
      }

      if(min_costs[i] < min_cost_adjacency_weight) {
        min_cost_adjacency_label = i;
        min_cost_adjacency_weight = min_costs[i];
      }
    }
    if(min_cost_adjacency_label == no_label) {
      break;
    }

    is_visits[min_cost_adjacency_label] = true;

    for(int i = 0; i < matrix_graph.size(); i++) {
      if(matrix_graph[min_cost_adjacency_label][i] == infinity) {
        continue;
      }

      if(min_costs[min_cost_adjacency_label] + matrix_graph[min_cost_adjacency_label][i] < min_costs[i]) {
        min_costs[i] = min_costs[min_cost_adjacency_label] + matrix_graph[min_cost_adjacency_label][i];
      }
    }
  }

  return min_costs;
}

int main() {
  int vertex_num;
  cin >> vertex_num;
  MatrixGraph matrix_graph(vertex_num, vector<int>(vertex_num, infinity));

  for(int i = 0; i < vertex_num; i++) {
    int label, degree;
    cin >> label >> degree;
    for(int j = 0; j < degree; j++) {
      int adjacency_label;
      int adjacency_weight;
      cin >> adjacency_label >> adjacency_weight;
      matrix_graph[label][adjacency_label] = adjacency_weight;
    }
  }

  vector<int> min_consts = calc_shortest_path(matrix_graph, 0);

  for(int i = 0; i < min_consts.size(); i++) {
    cout << i << ' ' << min_consts[i] << endl;
  }
}