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 <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int MAXN = 1e4 + 7, INF = 5e5 + 7;
int d[MAXN];
struct node {
	int id, dist;
	node(int id, int dist) :id(id), dist(dist) {}
	bool operator < (const node &rhs) const {
		return dist > rhs.dist;
	}
};
vector<pair<int, int> > G[MAXN];
priority_queue<node> nodes;
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i < n; i++) {
    	d[i] = INF;
	}
    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));
		}
	}
	nodes.push(node(0, 0));
	while (!nodes.empty()) {
		node tmp = nodes.top();
		nodes.pop();
		if (tmp.dist > d[tmp.id]) continue;
		int cnt = G[tmp.id].size();
		for (int i = 0; i < cnt; i++) {
			if (d[G[tmp.id][i].first] > d[tmp.id] + G[tmp.id][i].second) {
				d[G[tmp.id][i].first] = d[tmp.id] + G[tmp.id][i].second;
				nodes.push(node(G[tmp.id][i].first, d[G[tmp.id][i].first]));
			}
		}
	}
	for (int i = 0; i < n; i++) {
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
static const int INFTY = (1 << 21);

int n,M[100][100];

void dikstra(){
  int u,minu,d[100],p[100],color[100];
  for (int i = 0; i < n; i++) {
    color[i] = 0;
    d[i] = INFTY;
  }
  d[0] = 0;
  color[0] = 1;

  while (1) {
    minu = INFTY;
    u = -1;
    for (int i = 0; i < n; i++) {
      if (color[i] != 2 && d[i] < minu) {
        minu = d[i];
        u = i;
      }
    }
    if (u == -1)break;
    color[u] = 2;

    for (int v = 0; v < n; v++) {
      if (color[v] != 2 && M[u][v] != INFTY) {
        if (d[u] + M[u][v] < d[v]) {
          d[v] = d[u] + M[u][v];
          color[v] = 1;
        }
      }
    }
  }
  for (int i = 0; i < n; i++) {
    cout << i << " " <<(d[i] == INFTY ? -1 : d[i])<< endl;
  }

}
int main() {
  int u,v,k,c;
  cin >> n/* variable */;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      M[i][j] = INFTY;
    }
  }
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      cin >> v >> c;
      M[u][v] = c;
    }
  }

  dikstra();

  return 0;
}

C++: #include<stdio.h>
#include<algorithm>
#include<iostream>
using namespace std;
#define INF 1<<21
int main()
{
	long long int min,n,u,k,v,c,dist[100][100],s,cost[100],t[100],l=1;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			dist[i][j]=INF;
			cost[i]=INF;
			t[i]=-1;
		}
	}
	min=INF;
	dist[0][0]=0;
	for(int i=1;i<=n;i++)
	{
		cin>>u;
		cin>>k;
		for(int i=1;i<=k;i++)
		{
			cin>>v>>c;
			dist[u][v]=c;
		}
	}
	s=0;
	cost[s]=0;
	while(l!=n)
	{
		for(int i=0;i<n;i++)
		{
			if(dist[s][i]!=INF)
			{
				if(cost[s]+dist[s][i]<cost[i])
				{
					cost[i]=cost[s]+dist[s][i];
				}
				
			}
		}
		t[s]=1;
		for(int i=1;i<n;i++)
		{
			if(cost[i]<min&&t[i]==-1)
			{
				min=cost[i];
				s=i;
			}
		}
		min=INF+1;
		l++;
	}
	for(int i=0;i<n;i++)
	{
		cout<<i<<" "<<cost[i]<<endl;
	}
	return 0;
}

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;
  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;
}