Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include <utility>
#include <vector>
#include <queue>
#include <functional>
#include <cassert>

using namespace std;

class Dijkstra {
#define MAX_V 101
  typedef pair<int, int> P;

private:
  const int INF = 1e9 + 10;
  struct Edge {
    int to, cost;
    Edge(int to, int cost): to(to), cost(cost) { }
  };

  int V;
  vector<Edge> G[MAX_V];

public:

  Dijkstra(int V): V(V) { 
    if (V >= MAX_V) {
      assert(false);
    }
  }

  void AddEdge(int from, int to, int cost) {
    G[from].push_back(Edge(to, cost));
  }

  vector<int> Solve(int s) {
    priority_queue<P, vector<P>, greater<P>> que;
    vector<int> d(V, INF);
    d[s] = 0;
    que.push(P(0, s));

    while (!que.empty()) {
      P p = que.top(); que.pop();
      int v = p.second;
      if (d[v] < p.first) {
        continue;
      }
      for (int i = 0; i < G[v].size(); i++) {
        Edge e = G[v][i];
        if (d[e.to] > d[v] + e.cost) {
          d[e.to] = d[v] + e.cost;
          que.push(P(d[e.to], e.to));
        }
      }
    }

    return d;
  }
};

#include <iostream>


int main() {
  int n;
  cin >> n;
  Dijkstra dijkstra(n);
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int t, c;
      cin >> t >> c;
      dijkstra.AddEdge(u, t, c);
    }
  }

  vector<int> d = dijkstra.Solve(0);

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

  return 0;
}

C++: #include <iostream>
using namespace std;
#include <algorithm>
#define INF 1000000

int flg[100];

bool check(int p){

	if (flg[p] == 1) return false;
	return true;
}

int main(void){

	int n;

	cin >> n;
	int u, k;
	int date[100][100]; //date[??????????????????][?????´?????????]
	int dis[100]; //0????????????????????????????????¢

	memset(date, INF, sizeof(date));
	memset(dis, INF, sizeof(dis));
	memset(flg, 0, sizeof(flg));
	date[0][0] = 0;
	dis[0] = 0;
	for (int i = 0; i < n; i++){

		cin >> u >> k;
		for (int j = 0; j < k; j++){

			int v, c;
			cin >> v >> c;
			date[u][v] = c;
		}
	}

	while(1){
		int mini = INF;
		int p = -1;
		for (int i = 0; i < n; i++){
			if (check(i) && mini > dis[i]){
				p = i;
				mini = dis[i];
			}
		}
		if (p == -1) break;
		flg[p] = 1;
		for (int i = 0; i < n; i++){
			if (check(i) && dis[i] > dis[p] + date[p][i]){
				dis[i] = dis[p] + date[p][i];
			}
		}
	}

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

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

#define rep(i, n) for(int (i) = 0; (i) < (n); (i)++)
#define repp(i, n, m) for(int (i) = (n); (i) < (m); (i)++)
#define repn(i, n) for(int (i) = 1; (i) <= (n); (i)++)
#define repr(i, n) for(int (i) = (n-1); (i) >= 0; (i)--)
#define all(x) (x).begin(), (x).end()
#define lint long long
#define ulint unsigned long long
#define ldou long double
#define fi first
#define se second
#define setpre(x) std::cout << fixed << setprecision(x)
#define ii(x) int x; cin >> (x)
#define ii2(x, y) int x, y; cin >> (x) >> (y)
#define ii3(x, y, z) int x, y, z; cin >> (x) >> (y) >> (z)
#define out(x) cout << (x) << endl
#define outs(x) cout << (x) << " "
#define yn(x) cout << ((x)?("Yes"):("No")) << endl
#define YN(x) cout << ((x)?("YES"):("NO")) << endl
#define bit_c(x) __builtin_popcountll(x)

inline void logger(){ std::cout << " [LOGGER] " << endl; }
template<typename A, typename... B>
void logger(const A& a, const B&... b){
    cout << a << " , "; logger(b...);
}

typedef pair<lint, lint> P;
const lint MOD = 1000000007;
const lint MOD9 = 998244353;
const lint INF = MOD * MOD;
const int MAX = 200005;

/* ...o(^-^)o... */

struct edge{
    int from, to; lint cost;
    edge(int f, int t, lint c) : from(f), to(t), cost(c) {}
    edge(int t, lint c) : from(-1), to(t), cost(c) {}
};

struct dijkstra{
    vector<vector<edge> > G;
    vector<lint> d;
    int V, s;
    dijkstra(vector<vector<edge> > _G, int _s) : G(_G), s(_s){
        init();
    }
    void init(){
        V = G.size();
        d = vector<lint>(V, INF);
        priority_queue<P, vector<P>, greater<P> > que; que.push(P(0, s));
        d[s] = 0;
        while(!que.empty()){
            P p = que.top(); que.pop();
            int v = p.second;
            if(d[v] < p.first) continue;
            for(int i = 0; i < G[v].size(); i++){
                edge e = G[v][i];
                if(d[e.to] > d[v] + e.cost){
                    d[e.to] = d[v] + e.cost;
                    que.push(P(d[e.to], e.to));
                }
            }
        }
    }
    int dist(int t){
        return d[t];
    }
};

int main(){
    int n; cin>>n;
    vector<vector<edge>> G(n);
    rep(i,n){
        int u,k; cin>>u>>k;
        rep(j,k){
            lint v,c; cin>>v>>c;
            G[u].push_back(edge(u,v,c));
        }
    }

    dijkstra dij(G, 0);
    rep(v, n){
        outs(v); out(dij.dist(v));
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define M 1000000007
#define ff first.first
#define fs first.second
#define sf second.first
#define ss second.second
typedef pair<int,int> P;
typedef pair<P,P> PP;
int main(void)
{
	int i,j,k,u,n,flg[1001],v,c,sum,ky[1001],t,min,g;
	PP ke[1001];
	scanf("%d",&n);
	sum=0;
	for(i=0;i<n;i++) ky[i]=M,flg[i]=0;
	ky[0]=0;
	for(i=0;i<n;i++){
		scanf("%d%d",&u,&k);
		for(j=sum;j<k+sum;j++){
			scanf("%d%d",&v,&c);
			ke[j].ff=u , ke[j].fs=v , ke[j].sf=c;
		}
		sum+=k;
	}
	sort(ke,ke+sum);
	//for(i=0;i<sum;i++) printf("ke[%d].ff=%d ke[%d].fs=%d ke[%d].sf=%d\n",i,ke[i].ff,i,ke[i].fs,i,ke[i].sf);
	for(i=0;i<sum;i++){
		min=M;
		for(j=0;j<sum;j++) if(flg[j]==0&&min>ky[j]) g=j,min=j;
		flg[g]=1;
		if(min==M) break;
		for(j=0;j<sum;j++){
			t=ky[ke[j].ff]+ke[j].sf;
			if(ky[ke[j].fs]>t) g=j,ky[ke[j].fs]=t;
		}
	}
	for(i=0;i<n;i++) printf("%d %d\n",i,ky[i]);
	return 0;
}