Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

func (pq *PQ) Push(x interface{}) {
	*pq = append(*pq, x.(Node))
}

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, d[i])
	}
	wtr.Flush()
}

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

using ll = long long;
using namespace std;
/* initialize */
int n;
vector<pair<int, int> > adj[10000];

void dijkstra(){
    priority_queue<pair<int,int> > PQ;
    int color[10000];
    int d[10000];
    for (int i = 0; i < n; ++i) {d[i] = INT32_MAX; color[i] = 0;};
    d[0] = 0;
    PQ.push(make_pair(0, 0));
    color[0] = 1;
    while (!PQ.empty()){
        pair<int, int> f = PQ.top(); PQ.pop();
        int u = f.second;
        color[u] = 2;
        if (d[u] < f.first * (-1)) continue;

        for (int j = 0; j < adj[u].size(); ++j) {
            int v = adj[u][j].first;
            if(color[v] == 2) continue;
            if (d[v] > d[u] + adj[u][j].second){
                d[v] = d[u] + adj[u][j].second;
                PQ.push(make_pair(d[v]*-1, v));
                color[v] = 1;
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i << " " << (d[i] == INT32_MAX ? -1 : d[i]) << "\n";
    }
};
/* main */
int main() {
    int k, u, v, c;

    cin >> n;
    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; ++j) {
            scanf("%d %d", &v, &c);
            adj[u].emplace_back(v,c);
        }
    }
    dijkstra();
    return 0;
}

C++: #include <stdio.h>
#include <vector>
#include <queue>

using namespace std;
#define MAX_N (10010)
#define INF (1000000100)
typedef struct {
    int to;
    int w;
} Edge;

vector<Edge> G[MAX_N];
int n;

int dist[MAX_N];
bool arrived[MAX_N];

void dijkstra(int s)
{
    priority_queue< pair<int, int> > PQ;
    for ( int i = 0; i < n; i++ ) {
	dist[i] = INF;
	arrived[i] = false;
    }

    dist[s] = 0;
    PQ.push(make_pair(0, 0));

    while ( !PQ.empty() ) {
	pair<int, int> u = PQ.top(); PQ.pop();
	if ( u.second > dist[u.first] ) continue;
	arrived[u.first] = true;
	
	for ( int i = 0; i < G[u.first].size(); i++ ) {
	    Edge e = G[u.first][i];
	    if ( !arrived[e.to] && dist[e.to] > (dist[u.first] + e.w) ) {
		dist[e.to] = dist[u.first] + e.w;
		PQ.push(make_pair(e.to, dist[e.to]));
	    }
	}
    }

}

int main()
{
    scanf("%d", &n);
    
    for ( int i = 0; i < n; i++ ) {
	int u, k;
	scanf("%d %d", &u, &k);

	for ( int j = 0; j < k; j++ ) {
	    int v, c;
	    Edge e;
	    scanf("%d %d", &v, &c);
	    e.to = v;
	    e.w = c;
	    G[u].push_back(e);
	}
    }

    dijkstra(0);

    for ( int i = 0; i < n; i++ ) {
	printf("%d %d\n", i, dist[i]);
    }

    return 0;
}

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

#define INF 1000000000
using namespace std;

struct edge {
    int from;
    int to;
    int w;
};
struct node {
    node() : id {-1}, d {INF}, ns {} {};
    node(int i, vector<edge>& vec) : id {i}, d {INF}, ns {vec} {};
    int id;
    int d;
    vector<edge> ns;
};

struct node_s {
    int id;
    int d;
};

vector<int> dijkstra(node* graph, int n, int st){
    auto ds = vector<int>(n, INF);
    auto comp = [](node_s* x, node_s* y){return x->d > y->d;};
    priority_queue<node_s*, vector<node_s*>, decltype(comp)> que(comp);
    node_s* start = new node_s {graph[st].id, 0};
    que.push(start);
    while(que.size()){
        node_s* n = que.top();
    /    cout << n->id << ' ' << n->d << endl;
        que.pop();
        if(n->d < ds[n->id]){
            ds[n->id] = n->d;
            for(auto e : graph[n->id].ns){
                if(ds[e.to] < INF){
                    continue;
                }
                node_s* next_n = new node_s {graph[e.to].id, ds[n->id] + e.w};
                que.push(next_n);
            }
        }
        delete n;
    }
    return ds;
}

int main(){
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);
    int n;
    cin >> n;
    node graph[n];
    for(int i = 0; i < n; ++i){
        int id;
        int m;
        cin >> id >> m;
        auto vec = vector<edge>(m);
        int v, c;
        for(int j = 0; j < m; ++j){
            cin >> v >> c;
            vec[j] = edge {id, v, c};
        }
        graph[id] = node(id, vec);
    }
    auto ds = dijkstra(graph, n, 0);
    for(int i = 0; i < n; ++i){
        cout << i << ' ' << ds[i] << endl;
    }
}