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 <limits>

constexpr int MAXN = 100;
int G[MAXN][MAXN];
int P[MAXN];
int D[MAXN];
int C[MAXN];

constexpr int MAXINT = std::numeric_limits<int>::max();

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

    for (int i = 0 ; i < n; i++) {
        for (int j = 0 ; j < n; j++) {
            G[i][j] = MAXINT;
        }
    }

    for (int i = 0; i < n; i++) {
        D[i] = MAXINT;
    }

    for (int i = 0; i < n; i++) {
        int id, e_num;
        std::cin >> id >> e_num;
        for (int j = 0; j < e_num; j++) {
            int t;
            std::cin >> t;
            std::cin >> G[id][t];
        }
    }

    int r = 0;
    D[r] = 0;
    while (true) {
        int mincost = MAXINT;
        int m;
        for (int i = 0; i < n; i++) {
            if ((C[i] == 0) && (D[i] < mincost)) {
                mincost = D[i];
                m = i;
            }
        }

        if (mincost == MAXINT) {
            break;
        }

        C[m] = 1;
        for (int i = 0; i < n; i++) {
            if ((C[i] != 1) && (G[m][i] != MAXINT)&& ((D[m] + G[m][i]) < D[i])) {
                P[i] = m;
                D[i] = D[m] + G[m][i];
            }
        }
    }

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

}

C++: #include <bits/stdc++.h>
using namespace std;
static const int M=10000;
static const int INF=(1<<20);
int n;
vector<pair<int,int > > a[M];
void dijkstra(){
	priority_queue<pair<int,int> > Q;
	int col[M];
	int d[M];
	for(int i=0;i<n;i++){
		col[i]=0;
		d[i]=INF;
	}
	d[0]=0;col[0]=1;
	Q.push(make_pair(0,0));
	while(!Q.empty()){
		pair<int,int>f=Q.top();Q.pop();
		int u=f.second;col[u]=2;
		if(d[u]<f.first*(-1))continue;
		for(int j=0;j<a[u].size();j++){
			int v=a[u][j].first;
			if(col[v]==2)continue;
			if(d[v]>d[u]+a[u][j].second){
				d[u]=d[u]+a[u][j].second;
				Q.push(make_pair(d[v]*(-1),v));
				col[v]=1;
			}
		}
	}
	for(int i=0;i<n;i++)cout<<i<<' '<<(d[i]==INF?-1:d[i])<<endl;
}
int main() {
	int k,u,v,c;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>v>>c;
			a[u].push_back(make_pair(v,c));
		}
	}
	dijkstra();
}

C++: #include <bits/stdc++.h>
#define MAX_E 1000000
#define MAX_V 100000
#define INF 1e9
typedef long long ll;
using namespace std;
/*??????????????????????????? O(V*E)*/

//??????from????????????to???????????????cost??????
struct edge{int from, to, cost;};
edge es[MAX_E]; //???
ll d[MAX_V];   //???????????¢
int V,E;        //V???????????°???E????????°

//s???????????????????????????????????????????????¢????±???????.
void Bellman_Ford(int s){
  for(int i=0; i<V ;i++) d[i]=INF;
  d[s]=0;
  while(true){
    bool update=false;
    for(int i=0; i<E ;i++){
      edge e = es[i];
      if(d[e.from] != INF && d[e.to]> d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	update = true;
      }
    }
    if(!update) break;
  }
}

//true??????????????????????????¨??????
bool find_negative_loop(){
  memset(d,0,sizeof(d));

  for(int i=0; i<V ;i++){
    for(int j=0; j<E ;j++){
      edge e = es[j];
      if(d[e.to] > d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	
	//n??????????????´??°???????????????????????????????????¨?????????
	if(i == V-1) return true;
      }
    }
  }
  return false;
}

int main(){
  cin>>V;
  for(int i=0;i<V;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0,v,c;j<k;j++){
      cin>>v>>c;
      es[E++]=(edge){u,v,c};
    }
  }
  Bellman_Ford(0);
  for(int i=0;i<V;i++)
    cout<<i<<' '<<d[i]<<endl;
  /*  for(int i=0;i<V;i++){
    Bellman_Ford(i);
    cout <<i<<" "<<d[0]<<endl;
  }*/
}

C++: #include<stdio.h>
#include<string.h>
int n, dis[105], a[105][105];
bool vst[105];
void dijkstra()
{
    memset(vst, 0, sizeof(vst));
    memset(dis, 0x3f3f3f3f, sizeof(dis));
    dis[0] = 0;
    for(int i = 0; i < n; i++)
    {
        int k = n;
        for(int j = 0; j < n; j++)
            if(!vst[j] && dis[k] > dis[j]) k = j;
        vst[k] = 1;
        for(int j = 0; j < n; j++)
            if(!vst[j] && dis[j] > dis[k] + a[k][j])
                dis[j] = dis[k] + a[k][j];
    }
}
int main()
{
    scanf("%d", &n);
    memset(a, 0x3f3f3f3f, sizeof(a));
    for(int i = 1; i <= n; i++)
    {
        int m, j;
        scanf("%d%d", &m, &j);
        while(j--){
            int k, t;
            scanf("%d%d", &k, &t);
            if(t < a[m][k]) a[m][k] = t;
        }
    }
    dijkstra();
    for(int i = 0; i < n; i++)
        printf("%d %d\n", i, dis[i]);
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(void){
	int n;
	int u,k,v,c;
	int i,j;
	int MAX=INT_MAX;
	int box[101][101];
	cin>>n;
	for(i=0;i<n;i++){
		for(j=0;j<n;j++){
			if(i==j)	box[i][j]=0;
			else		box[i][j]=MAX;
		}
	}
	for(i=0;i<n;i++){
		cin>>u>>k;
		for(j=0;j<k;j++){
			cin>>v>>c;
			box[u][v]=c;
		}
	}
	// for(i=0;i<n;i++){
		// for(j=0;j<n;j++){
			// if(box[i][j]==MAX)	cout<<"★"<<" ";
			// else				cout<<box[i][j]<<" ";
		// }
		// cout<<endl;
	// }
	for(k=0;k<n;k++){
		for(i=0;i<n;i++){
			for(j=0;j<n;j++){
				if(box[i][k]!=MAX&&box[k][j]!=MAX){
					box[i][j]=min(box[i][j],box[i][k]+box[k][j]);
				}
			}
		}
	}
	// for(i=0;i<n;i++){
		// for(j=0;j<n;j++){
			// if(box[i][j]==MAX)	cout<<"★"<<" ";
			// else				cout<<box[i][j]<<" ";
		// }
		// cout<<endl;
	// }
	for(i=0;i<n;i++){
		cout<<i<<" "<<box[0][i]<<endl;
	}
	return 0;
}