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>
using namespace std;
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int INF = 1<<21;
int main(int argc, const char * argv[]) {
    int n;
    cin >> n;
    int G[n][n];
    int d[n];
    int p[n];
    int color[n];
    for(int i=0;i<n;i++){
        for (int j=0; j<n; j++) {
            G[i][j] = -1;
        }
    }
    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;
            G[u][v] = c;
        }
    }
    
    for (int i=0; i<n; i++) {
        color[i] = WHITE;
        p[i] = -1;
        d[i] = INF;
    }
    
    while(true){
        d[0] = 0;
        p[0] = 0;//?
        int u;
        int mincost = INF;
        //???????????????????±????
        for(int i=0;i<n;i++){
            if(d[i]<mincost && color[i]!=BLACK){
                mincost = d[i];
                u = i;
            }
        }
        color[u] = BLACK;
        if(mincost==INF) break;//?¶????????????????????????°??±?????£????????¨???
        
        for(int v=0;v<n;v++){
            if(G[u][v] != -1 && d[v]>d[u]+G[u][v]){
               d[v] = d[u] + G[u][v];
               color[v] = GRAY;//??????????????????
               p[v] = u;
            }
        }
    }
    for(int i=0;i<n;i++){
        cout <<  i << " " << d[i] << endl;
    }
    return 0;
}

C++: #include <cstdio>
#include <queue>
#include <vector>
using namespace std;
#define INF 1 << 30
typedef pair<int, int> P;

int n, M[100][100], d[100];

void dijkstra(void) {
    int i, u, v;
    P t;
    priority_queue<P, vector<P>, greater<P> > pq;

    pq.push(make_pair(0, 0));
    while (!pq.empty()) {
        t = pq.top(); pq.pop();
        v = t.first;
        u = t.second;

        if (d[u] != INF) continue;
        d[u] = v;

        for (i = 0; i < n; i++) {
            if (d[i] != INF || M[u][i] == INF) continue;
            pq.push(make_pair(v + M[u][i], i));
        }
    }
}

int main(void) {
    int i, j, u, k, v, c;
    scanf("%d", &n);

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

    for (i = 0; i < n; i++) {
        scanf("%d %d", &u, &k);
        for (j = 0; j < k; j++) {
            scanf("%d %d", &v, &c);
            M[u][v] = c;
        }
    }

    dijkstra();

    for (i = 0; i < n; i++) printf("%d %d\n", i, d[i]);

    return 0;
}

C++: #include <iostream>
using namespace std;
int n,m[100][100],d[100];
void mins(){
    int u,min,color[100];
    for(int i=0;i<n;i++){
        d[i]=1000000000;
        color[i]=1;
    }
    d[0]=0;
    while(1){
        min=1000000000;
        u=-1;
        for(int i=0;i<n;i++){
            if(color[i]!=3&&d[i]<min){
                u=i;
                min=d[i];
            }
        }
        if(u==-1){
            break;
        }
        color[u]=3;
        for(int i=0;i<n;i++){
            if(m[u][i]!=-1){
                if(d[i]>min+m[u][i]){
                    d[i]=min+m[u][i];
                }
            }
        }
    }
}
int main(){
    cin>>n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            m[i][j]=-1;
        }
    }
    int a,k,c,v;
    for(int i=0;i<n;i++){
        cin>>a>>k;
        for(int j=0;j<k;j++){
            cin>>c>>v;
            m[a][c]=v;
        }
    }
    mins();
    for(int i=0;i<n;i++){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}

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

int x[1000][1000];
int y[1000];

int main() {
	memset(x, 127, sizeof(x));
	memset(y, 127, sizeof(y));
	int n, a, b, c, d;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> a >> b;
		for (int i = 0; i < b; i++) {
			cin >> c >> d;
			x[a][c] = d;
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			for (int k = 0; k < n; k++) {
				y[k] = min(y[k], y[j] + x[j][k]);
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << i << ' ' << y[i] << endl;
	}
	return 0;
}

C++: #define _GLIBCXX_DEBUG
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
typedef long long ll;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#include <bits/stdc++.h>
using namespace std;

#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INF 1000000010

int n;
int M[100][100];
int color[100],d[100],p[100];

void dik(int s){
  
  rep(i,n){
    color[i]=WHITE;
    d[i]=INF;
    p[i]=-1;
  }
  d[s]=0;
  
  int minc,u;
  while(1){
    minc=INF; 
    rep(i,n){
      if(color[i] != BLACK && d[i]<minc){
        minc=d[i];
        u=i;
      }
    }
    
    if(minc==INF) break;
    color[u]=BLACK;
    
    rep(v,n){
      if(color[v] != BLACK && M[u][v] != -1){
        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;
  
  rep(i,n){
    rep(j,n) M[i][j]=INF;
  }
  
  int x,y,z;
  rep(i,n){
    cin>>x>>y;
    rep(j,y){
      cin>>z;
      cin>>M[x][z];
    }
  }
  
  dik(0);
  rep(i,n) cout<<i<<" "<<d[i]<<endl;
  
  return 0;
}