Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

const BIG_COST = 200000

const (
	ST_NOT_YET = iota
	ST_JOINED
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nNodes := scanInt(sc)

	costs := make([][]int, nNodes)
	graph := make([][]int, nNodes)

	states := make([]int, nNodes)
	costSums := make([]int, nNodes)

	for i := 0; i < nNodes; i++ {
		costs[i] = make([]int, nNodes)
		costSums[i] = BIG_COST
	}

	for i := 0; i < nNodes; i++ {
		u := scanInt(sc)
		k := scanInt(sc)
		graph[u] = make([]int, k)
		for d := 0; d < k; d++ {
			v := scanInt(sc)
			graph[u][d] = v
			costs[u][v] = scanInt(sc)
		}
	}

	costSums[0] = 0
	for {
		minCost := BIG_COST
		var u int

		for i, cost := range costSums {
			if states[i] != ST_JOINED && cost < minCost {
				minCost = cost
				u = i
			}
		}

		if minCost == BIG_COST {
			break
		}

		states[u] = ST_JOINED

		for _, v := range graph[u] {
			cost := minCost + costs[u][v]
			if cost < costSums[v] {
				costSums[v] = cost
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i, cost := range costSums {
		fmt.Fprintf(w, "%d %d\n", i, cost)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;

constexpr int LEN = 105;
int a[LEN][LEN];

int dikstra(int g, const int n){
	int d[n];
	bool check[n] = {0};
	memset(d, 1, sizeof(d));
	d[0] = 0;

	while(true){
		int u;
		int min_cost = INT_MAX;
		rep(i, n){
			if(!check[i] && (d[i] < min_cost)) {
				min_cost = d[i];
				u = i;
			}
		}

		if(min_cost == INT_MAX) break;
		check[u] = true;

		rep(v, n){
			if(!check[v] && (a[u][v] > -1)){
				if((d[u] + a[u][v]) < d[v]){
					d[v] = d[u] + a[u][v];
				}
			}
		}
	}

	return d[g];
}

int main(){
	memset(a, -1, sizeof(a));
	int n; cin >> n;
	rep(i, n){
		int u, k; cin >> u >> k;
		rep(j, k){
			int v, c; cin >> v >> c;
			a[u][v] = c;
		}
	}

	rep(i, n) cout << i << ' ' << dikstra(i, n) << endl;

	return 0;
}

C++: import java.util.ArrayList;
import java.util.Arrays;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
    int[] distTo = null;
    int[] parentOf = null;

    public Dijkstra(ArrayList<ArrayList<Edge>> G){
        distTo = new int[G.size()];
        Arrays.fill(distTo, Integer.MAX_VALUE);
        parentOf = new int[G.size()];

        PriorityQueue<SDto> pq = new PriorityQueue<>();

        pq.add(new SDto(0, 0, -1));
        while (!pq.isEmpty()) {

            SDto optim = pq.poll();

            if (optim.d < distTo[optim.v]) {
                distTo[optim.v] = optim.d;
                parentOf[optim.v] = optim.from;
                for (Edge e : G.get(optim.v)) {
                    if (optim.from != e.v) { // prevent go back
                        pq.add(new SDto(e.v, distTo[optim.v] + e.c, optim.v));
                    }
                }

            }
        }

    }

    private static class SDto implements Comparable<SDto> { // Shortest distance to vertex
        int v, d, from;

        SDto(int v, int d, int from) {
            this.v = v;
            this.d = d;
            this.from = from;
        }

        @Override
        public int compareTo(SDto that) {
            if(this.d > that.d) return 1;
            else if(this.d < that.d) return -1;
            return 0;
        }


    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int n = in.nextInt();

        ArrayList<ArrayList<Edge>> G = new ArrayList<>(n);
        for (int i = 0; i < n; i++) {
            G.add(new ArrayList<>());
        }

        for (int i = 0; i < n; i++) {
            int u = in.nextInt();
            int k = in.nextInt();
            for (int j = 0; j < k; j++) {
                int v = in.nextInt(), c = in.nextInt();
                G.get(i).add(new Edge(v, c));
                G.get(v).add(new Edge(i, c));
            }
        }

        Main dijkstra = new Main(G);

        for (int i = 0; i < G.size(); i++) {
            System.out.printf("%d %d\n", i, dijkstra.distTo[i]);
        }
    }
}

class Edge {
    int v, c;

    Edge(int v, int c) {
        this.v = v;
        this.c = c;
    }

    @Override
    public String toString() {
        return String.format("(v=%d, c=%d)", v, c);
    }
}

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

using namespace std;

static const long long FAR = (1LL << 21);
static const int N = 100;

int n, m[N][N];
bool visited[N];
int d[N], p[N];

void dijskra(){
	for (int i = 0; i < n; ++i) {
		d[i] = FAR;
		visited[i] = false;
	}

	d[0] = 0;
	while (true) {
		int mi = FAR;
		int u = -1;
		for (int i = 0; i < n; ++i) {
			if (!visited[i] && d[i] < mi){
				u = i;
				mi = d[i];
			}
		}

		if (-1 == u) break;
		visited[u] = true;

		for (int v = 0; v < n; ++v) {
			if (!visited[v] && (m[u][v] != FAR) && (d[u] + m[u][v] < d[v])) {
				d[v] = d[u] + m[u][v];
			}
		}
	}

	for (int i = 0; i < n; ++i)
		cout << i << " " << ((d[i] == FAR) ? -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] = FAR;
	}

	for (int i = 0; i < n; ++i) {
		int u, k; cin >> u >> k;
		for (int j = 0; j < k; ++j)	{
			int v, e; cin >> v >> e;
			m[u][v] = e;
		}
	}
	dijskra();

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>

using namespace std;

#define MAX_N 100
#define INF 100000 * 100 + 1

int cost[MAX_N][MAX_N];
int d[MAX_N];
bool used[MAX_N];
int V;

void dijkstra(int s) {
	fill_n(d, V, INF);
	fill_n(used, V, false);
	d[s] = 0;

	while (1) {
		int v = -1;
		for (int u = 0; u < V; u++)
			if (!used[u] && (v == -1 || d[u] < d[v]))
				v = u;

		if (v == -1)
			break;

		used[v] = true;

		for (int u = 0; u < V; u++)
			d[u] = min(d[u], d[v] + cost[v][u]);
	}
}

int main() {
	int n;
	cin >> n;
	V = n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		fill_n(cost[u], n, INF);
		for (int j = 0; j < k; j++) {
			int v, c;
			cin >> v >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);
	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 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]+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>
int main(){
  int u,k,C,V,D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){     std::cin >> u >> k;
    for(int j=0;j<k;j++){   std::cin >> V >> C;
      D[u][V] = C;}}
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}