Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

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;
}