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;

const long MAX = 100;
const long INFTY = (1<<21);
const long WHITE = 0;
const long GRAY = 1;
const long BLACK = 2;

long n, M[MAX][MAX];

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

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

	d[0] = 0;
	color[0] = GRAY;
	while (1){
		minv = INFTY;
		long u = -1;
		for (long 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 (long 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 (long i = 0; i < n; i++){
		cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
	}
}

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

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

	dijkstra();

	return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <list>
using namespace std;

#define NODE_NUM 100

class Node
{
private:
	int next_node_list[NODE_NUM];
	int next_node_num;
	int next_weight_list[NODE_NUM];
public:
	Node();
	void AddNextNode(int id, int weight);
	void SetWeight(int weight);
	void DistributeWeight();
	int weight_from_0;
	bool check;
};

Node::Node()
{
	next_node_num = 0;
	weight_from_0 = -1;
	check = false;
}

Node *Node_list;
list<int> Distributed_node_list;

void Node::AddNextNode(int id, int weight)
{
	next_node_list[next_node_num] = id;
	next_weight_list[next_node_num] = weight;
	next_node_num++;
}

void Node::SetWeight(int weight)
{
	if (weight_from_0 == -1 || weight < weight_from_0) {
		weight_from_0 = weight;
	}
}

void Node::DistributeWeight()
{
	check = true;
	for (int i = 0; i < next_node_num; i++) {
		if (Node_list[next_node_list[i]].check == false) {
			Distributed_node_list.push_back(next_node_list[i]);
			Node_list[next_node_list[i]].SetWeight(weight_from_0 + next_weight_list[i]);
		}
	}
}

int main(void)
{
	//input
	int n;
	cin >> n;
	Node_list = new Node[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;
			Node_list[i].AddNextNode(v, c);
		}
	}

	//weight from 0 ?
	Node_list[0].SetWeight(0);
	Node_list[0].DistributeWeight();
	while (!Distributed_node_list.empty()) {
		int min_weight = Node_list[Distributed_node_list.front()].weight_from_0;
		list<int>::iterator min_idx = Distributed_node_list.begin();
		list<int>::iterator itr;
		for(itr = Distributed_node_list.begin(); itr != Distributed_node_list.end(); itr++){
			if (Node_list[*itr].weight_from_0 < min_weight) {
				min_weight = Node_list[*itr].weight_from_0;
				min_idx = itr;
			}
		}
		Node_list[*min_idx].DistributeWeight();
		Distributed_node_list.erase(min_idx);
	}
	
	//output
	for (int i = 0; i < n; i++) {
		cout << i << " " << Node_list[i].weight_from_0 << endl;
	}
	
	return 0;
}

C++: #include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;
typedef pair<int, int> P;
#define MAX_N (105)
#define MAX_C (100010)
#define INF (MAX_N * MAX_C)
vector<P> G[MAX_N];
int dist[MAX_N];
bool arrived[MAX_N];

int main()
{
    int n;
    scanf("%d", &n);
    
    for ( int i = 0; i < n; i++ ) {
	int u, k;
	scanf("%d %d", &u, &k);
	for ( int j = 0; j < k; j++ ) {
	    int v, c;
	    scanf("%d %d", &v, &c);
	    G[u].push_back( make_pair(v, c) );
	}
    }
    
    for ( int i = 0; i < n; i++ ) {
	dist[i] = INF;
    }

    dist[0] = 0;

    while ( true ) {
	int min_dist = INF;
	int u = -1;
	for ( int i = 0; i < n; i++ ) {
	    if ( !arrived[i] ) {
		if ( min_dist > dist[i] ) {
		    min_dist = dist[i];
		    u = i;
		}
	    }
	}
	
	if ( min_dist == INF ) break;
	arrived[u] = true;

	for ( int i = 0; i < G[u].size(); i++ ) {
	    P p = G[u][i];
	    int v = p.first;
	    int c = p.second;

	    if ( !arrived[v] ) {
		dist[v] = min( dist[v], dist[u] + c );
	    }
	}
    }

    for ( int i = 0; i < n; i++ ) {
	printf("%d %d\n", i, dist[i]);
    }

    return 0;
}

C++: #include <algorithm>
#include <cstdio>
#include <iostream> 
using namespace std;  
const int maxn=105;
const int INF = 0x3f3f3f3f;   
int Map[maxn][maxn]; 
int n;
int min(int x,int y)
{
	if(x<y) return x;
	else  return y;
 } 
void floyd()  
{  
    for(int k=0;k<n;k++)  
        for(int i=0;i<n;i++)  
            for(int j=0;j<n;j++)  
            Map[i][j]=min(Map[i][j],Map[i][k]+Map[k][j]);  
}  
int main()  
{   
    scanf("%d",&n);
	     for(int i = 0 ; i<n ; i++)
			for(int j = 0 ; j<n ; j++) 
				Map[i][j] = i==j?0:INF;
    for(int i=0;i<n;i++) 
    {   int a,m;
	    scanf("%d%d",&a,&m);
        for(int i=0;i<m;i++)  
        {  
            int b,w;  
            scanf("%d%d",&b,&w);  
            Map[a][b]=Map[b][a]=min(Map[a][b],w);  
        }
    }
        floyd();
        for(int i=0;i<n;i++)
        {
        printf("%d %d\n",i,Map[0][i]); 
		}  
    return 0;  
}