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 <vector>
#include <iostream>
#include <algorithm>
#include <limits>

using namespace std;
using graph = vector<vector<int>>;


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

    graph G(n, vector<int>(n, -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;
        }
    }

    // Dijkstra's algorithm
    vector<int> d(n, -1);
    vector<bool> visited(n, false);

    d[0] = 0;
    visited[0] = true;
    while (1) {
        int u = -1;
        int v = -1;
        int minw = numeric_limits<int>::max();
        for (int i = 0; i < n; ++i) {
            if (!visited[i])
                continue;
            for (int j = 0; j < n; ++j) {
                if (G[i][j] < 0)
                    continue;
                int w = G[i][j] + d[i];
                if (!visited[j] && w < minw) {
                    u = i;
                    v = j;
                    minw = w;
                }
            }
        }
        if (v < 0) {
            break;
        }
        d[v] = minw;
        visited[v] = true;
    }

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

    return 0;
}

C++: #include<stdio.h>
#include<stdlib.h>

#define rep( i ,end ) for( int i = 0 ; i < end ; ++i )
#define Nmax 100
#define INF ( INT_MAX / 10 )

int Node[ Nmax ][ Nmax ] ;

int min( int a ,int b )
{
	return a > b ? b : a ;
}

void Init( int ( *NODE )[ Nmax ] ,int N )
{
	rep( i ,N )
	{
		rep( j ,N )
		{
			NODE[ i ][ j ] = ( i == j ) ? 0 : INF ;
		}
	}
}



int main( void )
{
	int N ,V ,K ;
	int v ,cost ;
	scanf( "%d" ,&N ) ;

	Init( Node ,N ) ;

	rep( i ,N )
	{
		scanf( "%d %d" ,&V ,&K ) ;

		rep( j ,K )
		{
			scanf( "%d %d" ,&v ,&cost ) ;

			Node[ V ][ v ] = cost ;
		}
	}

	rep( u ,N )
	{
		rep( i ,N )
		{
			rep( j ,N )
			{
				Node[ i ][ j ] = min( Node[ i ][ j ] ,Node[ i ][ u ] + Node[ u ][ j ] ) ;
			}
		}
	}

	rep( u ,N )
	{
		printf( "%d %d\n" ,u ,Node[ 0 ][ u ] ) ;
	}

	return 0 ;
}

C++: #include <iostream>
using namespace std;
#define MAX 101
#define INFTY (1<<21)
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, M[MAX][MAX];
void dijkstra()
{
    int minv;
    int d[MAX], color[MAX], p[MAX];
    for(int i=0; i<MAX; i++)
    {
        color[i] = WHITE;
        d[i] = INFTY;
        p[i] = -1;
    }
    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] != -1)
            {
                if(d[u]+M[u][v] < d[v])
                {
                    d[v] = d[u] + M[u][v];
                    p[v] = u;
                    color[v] = GRAY;
                }
            }
        }
    }
    for(int i=0; i<n; i++)
    {
        cout << i << " " << 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 <stdio.h>
#define INF (1<<21)

int main(void)
{
 int i,j,n,m,u,k,l,v,c,a[10000],b[10000],d[10000][10000];

 scand("%d",&n);
 
 for(i=0;i<n;i++){
 	scanf("%d %d",&u,&k);
 	a[i]=INF;
 	b[i]=0;
 	for(j=0;j<k;j++){
 		scanf("%d %d",&v,&c);
 		d[u][v]=c;
 	}
 }
 a[0]=0;
 
 while(1){
 	
 	l=-1;
 	m=INF;
 	
 	for(i=0;i<n;i++){
 		if(a[i]<m && b[i]=0){
 			m=a[i];
 			l=i;
 		}
 	}
 	
 	if(l==-1) break;
 	
 	b[l]=1;
 	
 	for(i=0;i<n;i++){
 		if(a[i]>=d[l][i]+a[l]) a[i]=d[l][i]+a[l];
 	}
 }
 
 for(i=0;i<n;i++){
 	if(a[i]==INF) printf("%d -1\n",i);
 	else printf("%d %d\n",i,a[i]);
 }
 
 return 0;
}

 return 0;
}

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

struct Edge {
    int from, to, cost;
    Edge(int f, int t, int c) : from(f), to(t), cost(c) { }
    bool operator <(const Edge& e) const {
        return cost < e.cost;
    }
};

const int INF = (int)1e9;
typedef pair<int, int> P;

vector<int> dijkstra(const vector<vector<Edge> >& g, int s) {
    vector<int> res(g.size(), INF);
    priority_queue<P, vector<P>, greater<P> > Q;
    Q.push(P(0, s));
    res[s] = 0;
    while(!Q.empty()) {
        P p = Q.top(); Q.pop();
        if(p.first > res[p.second]) continue;
        for(int i = 0; i < (int)g[p.second].size(); i++) {
            Edge e = g[p.second][i];
            if(res[e.to] > p.first + e.cost) {
                res[e.to] = p.first + e.cost;
                Q.push(P(res[e.to], e.to));
            }
        }
    }
    return res;
}

int main() {
    int N; cin >> N;
    vector<vector<Edge> > es(N);
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k;
        while(k--) {
            int v, c; cin >> v >> c;
            es[u].push_back(Edge(u, v, c));
        }
    }
    vector<int> res = dijkstra(es, 0);
    for(int i = 0; i < N; i++) {
        cout << i << ' ' << res[i] << endl;
    }
}