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] = INFTY;
  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++: #define _CRT_SECURE_NO_WARNINGS

#include<fstream>
#include<iostream>
#include<string>
#include<iomanip>
#include<list>
#include<math.h>
#include<stack>
#include<queue>
#include<vector>
#include<algorithm>
#include<utility>

using namespace std;

int main(){
	int a[100][100];
	int n;
	cin >> n;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			a[i][j] = 10000000;
		}
		a[i][i] = 0;
	}

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		a[i][i] = 0;
		for (int j = 0; j < k; j++) {
			int c, v;
			cin >> v >> c;
			a[u][v] = c;
		}
	}
	for (int k = 0; k < n; k++) {
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				a[i][j] = min(a[i][j], a[i][k] + a[k][j]);
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << i << " " << a[0][i] << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define INF 1<<30
struct edge{int to,cost;};
vector<edge> G[101];
int d[101];
bool visited[101];

void dijkstra(int n){
  fill(d+1,d+101,INF);
  memset(visited,false,sizeof(visited));
  for(int i=0;i<n;++i){
    int id=-1;
    for(int j=0;j<n;++j){
      if(!visited[j])
        if(id==-1||d[id]>d[j]) id=j;
    }
    visited[id]=true;
    for(int j=0;j<G[id].size();++j){
      edge e=G[id][j];
      d[e.to]=min(d[e.to],d[id]+e.cost);
    }
  }
}
int main(){
  int n; cin>>n;
  for(int i=0;i<n;++i){
    int u,k; cin>>u>>k;
    for(int j=0;j<k;++j){
      int c,v; cin>>c>>v;
      edge e; e.to=c, e.cost=v;
      G[u].push_back(e);
    }
  }
  dijkstra(n);
  for(int i=0;i<n;++i) cout<<i<<" "<<d[i]<<endl;
  return 0;
}

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define INF INT_MAX/3
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)
using namespace std;
typedef pair<int, int> P;
typedef pair<llong, llong> LP;
typedef pair<int, P> PP;
typedef pair<llong, LP> LPP;

int dy[]={0, 0, 1, -1, 0};
int dx[]={1, -1, 0, 0, 0};

#define MAX_N 10000
int G[MAX_N][MAX_N];
int MIN_COSTS[MAX_N];

int main() {
  int n;
  cin >> n;
  REP(i, n) {
    REP(j, n) {
      G[i][j] = INT_MAX;
    }
    MIN_COSTS[i] = INT_MAX;
  }
  int u, k;
  int v, c;
  REP(i, n) {
    cin >> u >> k;
    REP(j, k) {
      cin >> v >> c;
      G[u][v] = c;
    }
  }

  priority_queue<P> q;
  int position;
  int new_cost;
  q.push(P(0, 0));
  while (q.size() != 0){
    position = q.top().first;
    MIN_COSTS[position] = q.top().second;
    q.pop();
    REP(i, n) {
      if (G[position][i] != INT_MAX) {
        new_cost = MIN_COSTS[position] + G[position][i];
        if (new_cost < MIN_COSTS[i]) {
          MIN_COSTS[i] = new_cost;
          q.push(P(i, new_cost));
        }
      }
    }
  }

  REP(i, n) {
    cout << i << ' ' << MIN_COSTS[i] << endl;
  }

  return 0;
}

C++: #include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef pair< int, int > Pi;
const int INF = 1 << 30;
struct edge: vector< Pi > {
  void add_edge(int to, int cost){
    push_back(Pi(to,cost));
  }
} info[100000];
int hoge[100000];

void bfs(const int& st, const int& V){
  fill_n( hoge, V, INF);
  queue< int > que;
  que.push(st);
  hoge[st] = 0;
  while(!que.empty()){
    int p = que.front();
    que.pop();
    for(int i = 0 ; i < info[p].size() ; i++){
      int cost = info[p][i].second;
      int to = info[p][i].first;
      if( cost + hoge[p] < hoge[to]){
        que.push(to);
        hoge[to] = cost + hoge[p];
      }
    }
  }
}

int main(){
  int N;
  scanf("%d", &N);
  for(int i = 0; i < N; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    while(k--){
      int v, c;
      scanf("%d %d", &v, &c);
      info[u].add_edge( v, c);
    }
  }
  bfs(0, N);
  for(int i = 0 ; i < N ; i++ ){
    printf("%d %d\n", i, hoge[i]);
  }
}