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>
#define INF (1<<21)
#define WHITE 1
#define BLACK 2
#define GRAY 3
#define neg -1
using namespace std;

int n;
int m[100][100];
vector<int> g;
vector<int> color;

void di(){
  int u, mincost;

  for(int i = 0; i < n; i++){
    g[i] = INF;
    color[i] = WHITE;
  }

  g[0] = 0;
  color[0] = GRAY;

  while(1){
    mincost = INF;
    u = -1;

    for(int i = 0; i < n; i++){
      if(mincost > g[i] && color[i] != BLACK){
	u = i;
	mincost = g[i];
      }
    }

    if(u == neg) break;

    color[u] = BLACK;

    for(int i = 0; i < n; i++){
      if(color[i] != BLACK && m[u][i] != INF){
	if(g[i] > (g[u] + m[u][i])){
	  g[i] = g[u] + m[u][i];
	  color[i] = GRAY;
	}
      }
    }
  }

  for(int i = 0; i < n; i++){
    cout << i << " " << (g[i] == INF ? neg:g[i]) << endl;

  }
}

int main()
{
  cin >> n;
  g.resize(n);
  color.resize(n);

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

  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;
    }
  }

  di();

  return 0;

}

C++: #include<iostream>
#include<vector>
using namespace std;
const int MAX = 100;
const int INF = 10000000;
int n, G[MAX][MAX];
int dis[MAX];
bool Flag[MAX] = { false };
void init()
{
	for (int i = 0; i < n; i++)
		dis[i] = G[0][i];
	Flag[0] = true;
}
void dijkstra()
{
	for (int k = 1; k <= n - 1; k++)
	{
		int min = INF;
		int u;
		for (int j = 0; j < n; j++)
			if (dis[j] > 0 && dis[j] < INF && !Flag[j] && dis[j] < min)
			{
				min = dis[j];
				u = j;
			}
		Flag[u] = true;
		for (int v = 0; v < n; v++)
			if (!Flag[v] && dis[u]+G[u][v] < dis[v])
				dis[v] = dis[u] + G[u][v];
	}
}
int main()
{
	cin >> n;
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			if (i != j)
				G[i][j] = INF;
			else
				G[i][j] = 0;
	for (int i = 0; i < n; i++)
	{
		int u, d;
		cin >> u >> d;
		for (int j = 0; j < d; j++)
		{
			int v, w;
			cin >> v >> w;
			G[u][v] = w;
		}
	}
	init();
	dijkstra();
	for (int i = 0; i < n; i++)
		cout << i << " " << dis[i] << endl;
}

C++: #include<stdio.h>
main()
{
  int i,j,n,g,count=0;
  int V,A,A1,V1;
  int G[101][101],c[101],INF[101],p[101],mincost;

  for(i = 0; i < 101; i++){
    for(j = 0; j < 101; j++)
      G[i][j] = -1;
  }

  scanf("%d",&n);

  for(i = 0; i < n; i++){
    scanf("%d%d",&V,&A);
    for(j = 0; j < A; j++){
      scanf("%d%d",&V1,&A1);
      G[A][A1] = A1;
    }
  }

  for(i = 0; i < n; i++){
    c[i] = 0;
    p[i] = -1;
    INF[i] = 10000001;
  }

  INF[0] = 0;

  while(1){
    mincost = 10000001;
    for(i = 0; i < n; i++){
      if(c[i] != 2 && INF[i] < mincost){
        mincost = INF[i];
        g = i;
      }
    }
    if(mincost == 10000001)break;

    c[g] = 2;


    for(i = 0; i < n; i++){
      if(G[g][i] != -1 && c[i] != 2 && (G[g][i]+INF[g]) < INF[i]){
        p[i] = g;
        INF[i] = G[g][i] + INF[g];
        c[i] = 1;
      }
    }
  }
INF[0] = 0;

  while(1){
    mincost = 10000001;
    for(i = 0; i < n; i++){
      if(c[i] != 2 && INF[i] < mincost){
        mincost = INF[i];
        g = i;
      }
    }
    if(mincost == 10000001)break;

    c[g] = 2;


    for(i = 0; i < n; i++){
      if(G[g][i] != -1 && c[i] != 2 && (G[g][i]+INF[g]) < INF[i]){
        p[i] = g;
        INF[i] = G[g][i] + INF[g];
        c[i] = 1;
      }
    }
  }
  for(i = 0; i < n; i++)printf("%d %d\n",i,INF[i]);
  return 0;
}