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<iostream>
#include<algorithm>
using namespace std;

#define INF 1000000

int n;
int cost[110][110], d[110];
bool used[110];

void dijkstra(int s){

  for(int i = 0;i < n;i++) d[i] = INF;
  for(int i = 0;i < n;i++) used[i] = false;
  
  d[s] = 0;
  
  while(true){
    int v = -1;
    
    for(int u = 0;u < n;u++){
      if(!used[u] && (v == -1 || d[u] < d[v])) v = u;
    }
    
    if(v == -1) break;
    used[v] = true;
    
    for(int u = 0;u < n;u++){
      d[u] = min(d[u], d[v] + cost[v][u]);
    }
  }
}

int main(){
  
  int u, k, v, c;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    for(int j = 0;j < n;j++){
      cost[i][j] = INF;
    }
  }
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v >> c;
      cost[u][v] = min(cost[u][v], c);
    }
  }
  
  dijkstra(0);
  
  for(int i = 0;i < n;i++) cout << i << " " << d[i] << endl;
  
  return 0;
}

C++: #include <cstdio>
#include <iostream>
using namespace std;
#define INF 0xfffffff
int dis[200][200];
int main()
{
	int n;
	while(scanf("%d",&n)!=EOF)
	{
		for(int i=0;i<n;i++)
            for(int j=0;j<n;j++)
            {
                if(i==j) 
				dis[i][j]=0;
                else dis[i][j]=INF;
            }
		for(int i=0;i<n;i++)
		{
			int a,b,c;
			scanf("%d",&a);
			int t;
			scanf("%d",&t);
			for(int j=0;j<t;j++)
			{
				scanf("%d %d",&b,&c);
				dis[a][b]=min(c,dis[a][b]);
			}
		}
		for(int k = 0; k < n; k++)  //枚举中间点（必须放最外层）
		  for(int i = 0; i < n; i++)  //枚举端点i
		    if(i != k)
		      for(int j = 0; j < n; j++)  //枚举端点j
		        if(i != j && j != k && dis[i][j] > dis[i][k] + dis[k][j])
		          dis[i][j] = dis[i][k] + dis[k][j];
		int f,g;
		f=0;g=0;
		dis[0][0]=0;
		for(g=0;g<n;g++)
		{
			printf ("%d %d\n",g,dis[f][g]);
		}
	}
}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <queue>
#include <bitset>
#include <utility>
#include <functional>
#include <numeric>

//TODO

template <class T>
using vec = std::vector<T>;

constexpr int nil = -1;
constexpr int inf = 1 << 30;

struct Edge
{
    int to;
    int cost;
};

vec<int> dijkstra(const vec<vec<Edge>>& edges)
{
    using namespace std;

    const int n = edges.size();
    vec<int> distances(n, inf);
    vec<bool> reached(n, false);

    distances[0] = 0;

    while (true)
    {
        int minCost {inf};
        int u {};

        for (int i = 0; i < n; ++i)
        {
            if (!reached[i] && distances[i] < minCost)
            {
                minCost = distances[i];
                u = i;
            }
        }

        if (minCost == inf)
            break;
        
        reached[u] = true;

        for (auto& e : edges[u])
        {
            distances[e.to] = min(distances[e.to], distances[u] + e.cost);
        }
    }

    return distances;
}

void solve()
{
    using namespace std;
    int n;
    cin >> n;

    //隣接リスト形式
    vec<vec<Edge>> edges(n);
    
    //入力
    for (int i = 0; i < n; ++i)
    {
        int v, k;
        cin >> v >> k;
        for (int j = 0; j < k; ++j)
        {
            int to, cost;
            cin >> to >> cost;
            edges[i].push_back({to, cost});
        }
    }

    auto d = dijkstra(edges);

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

int main()
{
    solve();
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#define MAX 101
#define INF 1000001
using namespace std;

int n, isSelected[MAX], dist[MAX];
vector<pair<int, int>> ver[MAX];

void initDijkstra(void);
void dijkstra(void);
bool doesFinished(void);

int main() {
	int i, j, id, k, v, c;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			ver[id].push_back(make_pair(v, c));
		}
	}

	initDijkstra();

	while (!doesFinished())dijkstra();

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

	return 0;
}

void initDijkstra(void) {

	dist[0] = 0;
	isSelected[0] = 1;
	for (int i = 1; i < n; i++)dist[i] = INF;

	vector<pair<int, int>>::iterator itv;

	for (itv = ver[0].begin(); itv != ver[0].end(); itv++) {
		dist[itv->first] = itv->second;
	}

}

void dijkstra(void) {
	int i, minu = -1, mindist = INF;
	vector<pair<int, int>>::iterator itv;

	for (i = 0; i < n; i++) {
		if (isSelected[i] == 0)continue;
		for (itv = ver[i].begin(); itv != ver[i].end(); itv++){
			if (isSelected[itv->first] == 1)continue;
			if (dist[itv->first] < mindist) {
				mindist = dist[itv->first];
				minu = itv->first;
			}
		}
	}
	isSelected[minu] = 1;
	//dist[minu] = dist[minp] + mindist;
	for (itv = ver[minu].begin(); itv != ver[minu].end(); itv++) {
		if (isSelected[itv->first] == 1)continue;
		dist[itv->first] = min(dist[minu] + itv->second, dist[itv->first]);
	}
}

bool doesFinished(void) {
	for (int i = 0; i < n; i++) {
		if (isSelected[i] == 0)return false;
	}
	return true;
}

C++: #include <bits/stdc++.h>
using ll = long long;
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a); i < int(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
const long long INFLL = 1LL << 60;
const int INFINT = 1 << 30;
const long long MOD = 1e9 + 7;

template <class T> void vecout(T V) {
    auto t = V.begin();
    while(t != V.end()) {
        cout << " " << *t++;
        // if(t != V.end()) cout << " ";
    }
    cout << endl;
};

class edge {
  public:
    int f;
    int t;
    int c;
    edge(int _f, int _t, int _c) {
        f = _f;
        t = _t;
        c = _c;
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, u, k, v, c;
    cin >> n;
    vector<edge> edges;

    int d[n + 1];
    fill(d, d + n, INFINT);
    d[0] = 0;
    rep(i, n) {
        cin >> u >> k;
        rep(j, k) {
            cin >> v >> c;
            edge tmp(u, v, c);
            edges.push_back(tmp);
        }
    }

    rep(i, n) {
        for(auto e : edges) {
            if(d[e.t] > d[e.f] + e.c) {
                d[e.t] = d[e.f] + e.c;
            }
        }
    }

    rep(i, n) cout << i << " " << d[i] << "\n";
}