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<stdio.h>
#include<iostream>
#include<algorithm>
#include<string>
#include<string.h>
#include<math.h>
#include<stdlib.h>
#include<vector>
#include<queue>
#include<map>
#define rep(index,num) for(int index=0;index<num;index++)
#define rep1(index,num) for(int index=1;index<=num;index++)
#define scan(argument) cin>>argument
#define prin(argument) cout<<argument<<endl
#define kaigyo cout<<endl
#define eps 1e-15
typedef long long ll;
using namespace std;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<pint> vpint;
int INF=1e+9+1;
int N,M[100][100];
int d[100],color[100],p[100];
void dijkstra(){
	int minv;
	rep(i,N){
		d[i]=INF;
		color[i]=0;
	}
	d[0]=0;
	color[0]=1;
	while(1){
		minv=INF;
		int u=-1;
		rep(i,N){
			if(minv>d[i]&&color[i]!=2){
				u=i;
				minv=d[i];
			}
		}
		if(u==-1) break;
		color[u]=2;
		rep(v,N){
			if(color[v]!=2&&M[u][v]!=INF){
				if(d[v]>d[u]+M[u][v]){
					d[v]=d[u]+M[u][v];
					color[v]=1;
				}
			}
		}
	}
}
int main(){
	scan(N);
	rep(i,N){
		rep(j,N){
			M[i][j]=INF;
		}
	}
	int k,c,u,v;
	rep(i,N){
		scan(u);scan(k);
		rep(j,k){
			scan(v);scan(c);
			M[u][v]=c;
		}
	}
	dijkstra();
	rep(i,N){
		printf("%d %d\n",i,(d[i]==INF ? -1 : d[i]));
	}
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <vector>

using namespace std;

#define INF (10000001)

typedef pair<int, int> Edge;

int main()
{
    priority_queue<Edge,vector<Edge>,greater<Edge> > pq;
    vector<vector<Edge> > e;
    vector<int> d;
    Edge etemp;
    int n,u,k,v,c;
    cin >> n;
    e.resize(n);
    d.resize(n);
    for(int i=0; i<n; ++i) {
        cin >> u >> k;
        for(int j=0; j<k; ++j) {
            cin >> v >> c;
            e[u].push_back(Edge{c,v});
        }
        d[u]=INF;
    }

    d[0]=0;
    for(auto x : e[0]) {
        pq.push(x);
    }
    while(!pq.empty()) {
        etemp=pq.top(); pq.pop();
        v=etemp.second;
        c=etemp.first;
        if(d[v]<c) continue;
        d[v]=c;
        for(auto x : e[v]) {
            if(d[x.second]<=c+x.first) continue;
            pq.push(Edge{c+x.first,x.second});
        }
    }
    for(int i=0; i<n; ++i) {
        cout << i << " " << d[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
const int INF = 100000;
using namespace std;

int main(void){
  bool used[100];
  int n, G[100][100], p[100];
  cin >> n;
  for(int i=0; i < 100; i++){
    used[i] = false;
    for(int j=0; j < 100; j++){
      G[i][j] = INF;
    }
  }
  for(int i=0; i < n; i++){
    int vtmp, k;cin >> vtmp >> k;
    for(int j=0; j < k; j++){
      int v, c; cin >> v >> c;
      G[vtmp][v] = c;   
    }
  }

  int d[100];
  for(int i=0; i < n; i++){
    d[i] = INF;
  }
  d[0] = 0;

  for(int i=0; i < n; i++){
    int mind = INF;
    int minind;
    for(int j=0; j < n; j++){
      if(used[j] == false && d[j] < mind){
        mind = d[j]; minind = j;
      }
    }
    used[minind] = true;
    for(int j=0; j < n; j++){
      if(used[j] == false && G[minind][j] != INF){
        if(d[minind] + G[minind][j] < d[j]){
          d[j] = d[minind] + G[minind][j];
          p[j] = minind;
        }
      }
    }
  }
  for(int i=0; i < n; 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 n, M[MAX][MAX];

void dijkstra() {
   int minv;
   int color[MAX], d[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) {
  	      	  minv = d[i];
  	      	  u = 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;
	int u, k, c, v;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][i] = 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();
	
	return 0;
}