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<queue>
#include<utility>
#include<climits>
#include<algorithm>
using namespace std;
typedef int Cost;
typedef int Node;

void dijkstra(int start,   vector<vector< pair<Node,Cost> > > m){
  vector<Cost> costs(m.size());
  bool visited[m.size()];

  fill(costs.begin(),costs.end(),INT_MAX);
  fill(visited,visited+m.size(),false);
  
  priority_queue<pair<Cost,Node> ,vector<pair<Cost,Node> >, greater<pair<Cost,Node> > > q;
  q.push(make_pair(0,start));
  while(!q.empty()){
    Cost c = q.top().first;
    Node n = q.top().second;
    q.pop();
    if(!visited[n]){
      costs[n] = c;
      for(auto &x:m[n]){
        int node = x.first;
        int cost = x.second;
        q.push(make_pair(cost+c,node));
      }
      visited[n] = true;
    }
  }
  for(int i = 0;i < costs.size();i++){
    cout << i << ' ' << costs[i] << endl;
  }
}

int main(){
  int n;
  cin >> n;
  vector<vector< pair<Node,Cost> > > m(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;
      m[u].push_back(make_pair(v,c));
    }
  }
  dijkstra(0,m);
}

C++: #include <bits/stdc++.h>



using namespace std;



static const int INF = 999999;



int main(){

	int n,array[100][100];



	for(int i=0; i<100; i++){

		for(int j=0; j<100; j++){

			if(i==j) array[i][j]=0;

			else array[i][j]=INF;

		}

	}

	

	cin>>n;



	for(int i=0; i<n; i++){

		int u,k;

		cin>>u>>k;

		for(int j=0; j<k; j++){

			int t,c;

			cin>>t>>c;

			array[u][t]=array[t][u]=c;

		}

	}



	int d[100];

	fill(d,d+n,INF);

	d[0]=0;

	bool flag[100]={};



	while(1){

		int u=-1,infn=INF;

		for(int i=0; i<n; i++){

			if(!flag[i] && d[i]<=infn){

				u = i;

				infn = d[u];

			}

		}

		if(u==-1) break;

		flag[u] = true;



		for(int i=0; i<n; i++){

			if(array[u][i]!=INF && !flag[i]){

				d[i] = min(d[i],d[u]+array[u][i]);

			}

		}

	}



	for(int i=0; i<n; i++){

		cout<<i<<" "<<d[i]<<endl;

	}



	return 0;

}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>

using namespace std;

#define MAX_N 100
#define INF 100001

int cost[MAX_N][MAX_N];
int d[MAX_N];
bool used[MAX_N];
int V;

void dijkstra(int s) {
	fill_n(d, V, INF);
	fill_n(used, V, false);
	d[s] = 0;

	while (1) {
		int v = -1;
		for (int u = 0; u < V; u++)
			if (!used[u] && (v == -1 || d[u] < d[v]))
				v = u;

		if (v == -1)
			break;

		used[v] = true;

		for (int u = 0; u < V; u++)
			d[u] = min(d[u], d[v] + cost[v][u]);
	}
}

int main() {
	int n;
	cin >> n;
	V = n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		fill_n(cost[u], n, INF);
		for (int j = 0; j < k; j++) {
			int v, c;
			cin >> v >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);
	for (int i = 0; i < n; i++) {
		cout << i << " " << d[i] << endl;
	}
	
	return 0;
}

C++: //By Vlgd
#include<bits/stdc++.h>
using namespace std;
const int INF=(1<<21);
const int N=100;
int G[N][N],n,vis[N]={0},dis[N];
void dij(int s){
	dis[s]=0;
	while(1){
		int min=INF,u=-1;
		for(int i=0;i<n;i++){
			if(!vis[i]&&min>dis[i]){
				min=dis[i];
				u=i;
			} 
		}
		if(u==-1) break;
		vis[u]=1;
		for(int v=0;v<n;v++)
			if(G[u][v]!=INF&&!vis[v])
				if(dis[v]>dis[u]+G[u][v]) 
					dis[v]=dis[u]+G[u][v];
	}
}
int main(){
	scanf("%d",&n);
	int u,v,deg,w;
	for (int i=0;i<n;i++){
		dis[i]=INF;
		for (int j=0;j<n;j++) G[i][j]=INF;
	}
	for (int i=0;i<n;i++){
		scanf("%d%d",&u,&deg);
		for (int j=0;j<deg;j++){scanf("%d%d",&v,&w);G[u][v]=w;}
	}
	dij(0);
	for (int i=0;i<n;i++) printf("%d %d\n",i,dis[i]);
	return 0;
}