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 min;
   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 ) {
      min = INFTY; 
      int a = -1;
      for ( int i = 0; i < n; i++ ) {
         if ( min > d[i] && color[i] != BLACK ) {
             a = i;
             min = d[i];
         }
      }
 
      if ( a == -1 ) break;
      color[a] = BLACK;
       
      for ( int v = 0; v < n; v++ ) {
         if ( color[v] != BLACK && M[a][v] != INFTY ) {
            if ( d[v] > d[a] + M[a][v] ) {
               d[v] = d[a] + M[a][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 < n; j++ ) {
         cin >> v >> c;
         M[u][v] = c;
      }
   }
 
   dijkstra();
 
   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;
  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][v]+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 <limits>
#define N 100
#define INF INT_MAX

using namespace std;

int n,M[N][N],d[N];

void dijkstra(int s){
  bool visited[n];
  for(int i=0;i<n;i++){
    visited[i]=false;
    d[i]=INF;
  }
  d[s]=0;
  while(1){
    int mincost=INF;
    int u;
    //find minimum d from non-visited nodes
    for(int i=0;i<n;i++){
      if(!visited[i] && d[i]<mincost){
        mincost=d[i];
        u=i;
      }
    }
    if(mincost==INF) break;

    visited[u]=true;
    //update d
    for(int v=0;v<n;v++){
      if(!visited[v] && M[u][v]!=INF){
        if(d[u]+M[u][v]<d[v]){
          d[v]=d[u]+M[u][v];
        }
      }
    }
  }
}

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

C++: #include<bits/stdc++.h>
using namespace std;
int a[110][110];
int n;
bool visited[110];
int dis[110];
void spfa() {
    int i;
    for(i=0; i<n; i++) {
        dis[i]=1e9+7;
        visited[i]=0;
    }
    queue<int> myqueue;
    while(!myqueue.empty())
    myqueue.pop();
    dis[0]=0;
    visited[0]=1;
    myqueue.push(0);
    int tmp;
    while(!myqueue.empty()) {
        tmp=myqueue.front();
        myqueue.pop();
        visited[tmp]=0;
        for(i=0; i<n; i++)
            if(dis[i]>dis[tmp]+a[tmp][i]) {
                dis[i]=dis[tmp]+a[tmp][i];
                if(!visited[i]) {
                    visited[i]=1;
                    myqueue.push(i);
                }
            }
    }
    return ;
}
int main(){
    scanf("%d",&n);
    int x,t,r,e;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            a[i][j]=i==j?0:1e9+7;
        }
    }
    for(int i=0;i<n;i++){
        scanf("%d%d",&x,&t);
        while(t--){
            scanf("%d%d",&r,&e);
            if(a[i][r]>e){
                a[i][r]=a[r][i]=e;
            }
        }
    }
    printf("0 0\n");
    spfa();
    for(int i=1;i<n;i++)printf("%d %d\n",i,dis[i]);
}