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>
#include <vector>
#include <climits>

class Nodes;

class Node {
public:
    Node(int n) : id(n), cost(INT_MAX) { }
    void addEdge(int to, int cost) { edgesTo.push_back(to); edgesCost.push_back(cost); }
    int getId() { return id; }
    int getCost() { return cost; }
    void setCost(int alt) { cost = alt; }
    void print() { std::cout << id << " " << cost << std::endl; }
    void printAll() {
        std::cout << id << " " << cost;
        for (std::vector<int>::iterator itr = edgesTo.begin(), itr2 = edgesCost.begin();  itr != edgesTo.end(); ++itr, ++itr2) {
            std::cout << " " << *itr << " " << *itr2;
        }
        std::cout << std::endl;
    }
    void updatesCost(Nodes* nodes);
private:
    int id;
    std::vector<int> edgesTo;
    std::vector<int> edgesCost;
    int cost;
};

class Nodes {
public:
    void readFromIn() {
        int size;
        std::cin >> size;
        for (int i=0; i<size; ++i) {
            int id;
            int sizeOfEdges;
            std::cin >> id >> sizeOfEdges;
            Node *node = new Node(id);
            for (int j=0; j<sizeOfEdges; ++j) {
                int to;
                int cost;
                std::cin >> to >> cost;
                node->addEdge(to, cost);
                //std::cout << to << cost << std::endl;
            }
            nodes.push_back(node);
        }
        nodes[0]->setCost(0);
    }
    std::vector<Node*>::iterator findNodeWithTheLeastDistance(std::vector<Node*> &queue) {
        std::vector<Node*>::iterator min=queue.begin();
        for (std::vector<Node*>::iterator itr=queue.begin()+1; itr != queue.end(); ++itr) {
            if ((*min)->getCost() > (*itr)->getCost()) {
                min = itr;
            }
        }
        return min;
    }
    void dijkstrasAlgorithm() {
        std::vector<Node*> queue(nodes);

        while (!queue.empty()) {
            std::vector<Node*>::iterator u = findNodeWithTheLeastDistance(queue);
            int n = (*u)->getId();
            //std::cout << "**" << n << std::endl;
            queue.erase(u);

            getNode(n)->updatesCost(this);
        }
    }
    void print() {
        for (std::vector<Node*>::iterator itr=nodes.begin(); itr != nodes.end(); ++itr) {
            (*itr)->print();
        }
    }
    Node* getNode(int n) {
        return nodes[n];
    }
private:
    std::vector<Node*> nodes;
};

void Node::updatesCost(Nodes* nodes) {
    for (std::vector<int>::iterator itr = edgesTo.begin(), itr2 = edgesCost.begin();  itr != edgesTo.end(); ++itr, ++itr2) {
    Node* v = nodes->getNode(*itr);
    int alt = cost + *itr2;
    if (alt < v->getCost()) {
        v->setCost(alt);
    }
    //nodes->print();
}
    /*
for (i=0; i<nodes[u]->sizeOfEdges; ++i) {
    int v = nodes[u]->edgesTo[i];
    int alt = nodes[u]->cost + nodes[u]->edgesCost[i];
    if (alt < nodes[v]->cost) {
        nodes[v]->cost = alt;
    }
}
*/
}

int main(int argc, char *argv[])
{
    Nodes nodes;

    nodes.readFromIn();
    nodes.dijkstrasAlgorithm();
    nodes.print();
    return 0;
}

C++: //さっさと済ませられるところはさっさと済ましてしまう．ただし注意深く
#include <cstdio>
#include <iostream>
#define MAX_VERTEXES 100
#define NIL -1
#define INFTY 20000000// >100*100000

using namespace std;

//think easy make easy

int n;//num of vertexes(頂点)
int matrix_graph[MAX_VERTEXES+1][MAX_VERTEXES+1];//0オリジン
bool vertex_set[MAX_VERTEXES+1];///0オリジン
int current_mincost[MAX_VERTEXES+1];//現時点での各頂点への最小コスト
bool candidate[MAX_VERTEXES+1];//次にvertex_setに加える頂点の候補

void findNextVertex(){
	int min_tmp=INFTY;
	int next_tmp = NIL;
	for(int i=0;i<n;i++){
		candidate[i] = false;
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(vertex_set[i] == true && vertex_set[j] == false){
				if(matrix_graph[i][j]+current_mincost[i] < current_mincost[j]
				   && matrix_graph[i][j] != NIL){
					   current_mincost[j]  = matrix_graph[i][j]+current_mincost[i];
					   candidate[j] = true;
				}
			}
		}
	}
	for(int i=0;i<n;i++){
		if(candidate[i] == true && current_mincost[i] < min_tmp){
			min_tmp = current_mincost[i];
			next_tmp = i;
		}
	}
	vertex_set[next_tmp] = true;
}

int main(){
	scanf("%d",&n);

	int v_num;
	int k;//v_numの出次数

	for(int i=0;i<n;i++){
		for(int j=0;j<=n;j++){
			matrix_graph[i][j] = NIL;
		}
	}

	for(int i=0;i<n;i++){
		scanf("%d",&v_num);
		scanf("%d",&k);

		for(int j=0;j<k;j++){
			int v_num2;
			int cst;
			scanf("%d",&v_num2);
			scanf("%d",&cst);
			matrix_graph[v_num][v_num2] = cst;
		}
	}

	for(int i=0;i<n;i++){
		vertex_set[i] = false;
		current_mincost[i] = INFTY;
	}
	/*確認用
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(j<n-1) printf("%d ",matrix_graph[i][j]);
			else printf("%d\n",matrix_graph[i][j]);
		}
	}
	*/

	vertex_set[0] = true;
	current_mincost[0] = 0;
	for(int i=1;i<n;i++){
		findNextVertex();
	}
	for(int i=0;i<n;i++){
		cout <<i <<" " <<current_mincost[i] <<endl;
	}


	return 0;
}