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++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>

using namespace std;

static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int NIL = -1;
static const int MAX = 100;
static const int INFTY = 10000000;


int colors[MAX] = { WHITE };	//各頂点の訪問状態
int graph[MAX][MAX] = { INFTY };
int d[MAX] = { INFTY };		//原点からの各頂点の距離
int p[MAX] = { NIL };		//親頂点

void dijkstra(int n) {

    d[0] = 0;
    colors[0] = WHITE;

    while (true) {

	int mincost = INFTY;
	int u;

	for (int i = 0; i < n; i++) {
	    //まだコストが確定しておらず、かつ現時点で仮コストが出ているもの
	    if (colors[i] != BLACK&&d[i] != INFTY) {

		//より小さいコストの原点からの距離があったら
		if (d[i] < mincost) {
		    mincost = d[i];
		    u = i;
		}
	    }
	}

	if (mincost == INFTY) {
	    break;
	}

	colors[u] = BLACK;

	//確定した頂点uからの近隣探索
	for (int i = 0; i < n; i++) {
	    
	    //まだ確定しておらずvから辺があれば
	    if (colors[i] != BLACK&&graph[u][i] != INFTY) {


		//現時点でiに行くコストより
		//頂点uを経由した方がコストが小さかったら
		if (d[u]+graph[u][i] < d[i]) {
		    d[i] = d[u] + graph[u][i];
		    p[i] = u;
		}

	    }

	}

    }
}

int main() {

    //cin.tie(0);
    //ios::sync_with_stdio(false);
    
    int n; scanf("%d", &n);
    int u; //頂点
    int k; //vからの辺の数
    int v; //uにつながる頂点v
    int c; //コスト

    //グラフ初期化
    for (int i = 0; i < n; i++) {
	for (int j = 0; j < n; j++) {
	    graph[i][j] = INFTY;
	}
    }
    
    //距離d初期化
    for(int i = 0; i < n; i++) {
	d[i] = INFTY;
    }

    //グラフ読み込み
    for (int i = 0; i < n; i++) {
	scanf("%d", &u);
	scanf("%d", &k);
	for (int j = 0; j < k; j++) {
	    scanf("%d", &v);
	    scanf("%d", &c);
	    graph[u][v] = c;
	}
    }


    //ダイクストラ法
    dijkstra(n);

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

    return 0;

}

C++: #include <iostream>
#include <algorithm>
using namespace std;

#define MAX_VERTEX 100
#define INF 1000000

int cost[MAX_VERTEX][MAX_VERTEX];
int d[MAX_VERTEX];
bool used[MAX_VERTEX];

int main() {
  int vertex_num;
  cin >> vertex_num;

  for(int i = 0; i < vertex_num; i++) {
    d[i] = INF;
    used[i] = false;
    for(int j = 0; j < vertex_num; j++) {
      cost[i][j] = INF;
    }
  }

  for (int i = 0; i < vertex_num; i++) {
    int vertex, out;
    cin >> vertex >> out;
    for(int j = 0; j < out; j++) {
      int to, c;
      cin >> to >> c;
      cost[vertex][to] = c;
    }
  }

  d[0] = 0;
  while(true) {
    int vertex = -1;
    for(int u = 0; u < vertex_num; u++) {
      if(!used[u] && (vertex == -1 || d[u] < d[vertex])) {
        vertex = u;
      }
    }

    if (vertex == -1) break;

    used[vertex] = true;

    for(int u = 0; u < vertex_num; u++) {
      d[u] = min(d[u], d[vertex] + cost[vertex][u]);
    }
  }

  for(int i = 0; i < vertex_num; i++) {
    cout << i << " " << d[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 M[MAX][MAX], color[MAX], d[MAX], p[MAX];

int n;

void dijkstra(int s){
    int u = s;
    for(int u = 0; u < n; u++){
        color[u] = WHITE;
        d[u] = INFTY;
    }
    d[s] = 0;
    p[s] = -1;

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

        color[u] = BLACK;

        for(int v = 0; v < n; v++){
            if(color[v] != BLACK && M[u][v] != INFTY){
                if(d[u] + M[u][v] < d[v]){
                    d[v] = d[u] + M[u][v];
                    p[v] = u;
                    color[v] = GRAY;
                }
            }
        }
    }
}
int main(){
    cin >> n;
    int u, k, v, c;

    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;
        }
    }

    dijkstra(0);

    for(int i = 0; i < n; i++){
        cout << i << " " << d[i] << endl;
    }

    return 0;
}