Go: package main

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

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	route := make([][]Node, n)
	weight := make([]int, n)
	for i := 0; i < n; i++ {
		weight[i] = NIL
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		route[i] = make([]Node, k)
		for j := 0; j < k; j++ {
			route[u][j] = Node{id: scanInt(), weight: scanInt()}
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for _, nextNode := range route[node.id] {
			if weight[nextNode.id] != NIL {
				continue
			}
			nextNode.weight += node.weight
			heap.Push(h, nextNode)
		}
	}

	for i, w := range weight {
		fmt.Println(i, w)
	}
}

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

const long long INFF = 1e18;

const int MAX_N = 11000;
using TYPE = long long; // ?????¢???????????\??????
vector<pair<int, TYPE> > G[MAX_N];

vector<TYPE> dijkstra(int start){
	vector<TYPE> dist(MAX_N, INFF);
	dist[start] = 0;//dist[i] :=???start->i?????§??????????????¢
	priority_queue<pair<TYPE, int>, vector<pair<TYPE, int> >, greater<pair<TYPE, int> > >  que;
	que.push(make_pair(0, start));
	while(!que.empty()){
		TYPE cost; int u;//????????§???????????£????????? ?????¨?????????
		cost = que.top().first, u = que.top().second;
		que.pop();
		if(dist[u] < cost) continue;
		for (auto tmp : G[u]){
			int v = tmp.first; TYPE time = tmp.second;//??£??\???????????? ?????????????????§????????????
			if(dist[v] > dist[u] + time){//u->v
				// if(dist[v] != INFF) printf("%f %fa\n", dist[v], dist[u] + time);
				dist[v] = dist[u] + time;
				que.push(make_pair(dist[v], v));
			}
		}
	}
	return dist;
}


int main(void) {
	int n; cin >> n;
	rep(q, n) {
		int u, k; cin >> u >> k;
		vector<int> v(k); vector<long long> c(k);
		rep(i, k) cin >> v[i] >> c[i];
		rep(i, k) G[u].push_back(make_pair(v[i], c[i]));
	}
	auto dist = dijkstra(0);
	rep(i, n) printf("%d %d\n", i, dist[i]);
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <limits>
using namespace std;

typedef pair<int,int> vec;

vector<vec> adj[10000];
int d[10000];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin>>n;
    for(int i=0; i<n; i++) d[i]=numeric_limits<int>::max();
    for(int i=0; i<n; i++) {
        int u,k;
        cin>>u>>k;
        adj[u].reserve(k);
        for(int j=0; j<k; j++) {
            int v,c;
            cin>>v>>c;
            adj[u].push_back(vec(v,c));
        }
    }
    priority_queue<vec, vector<vec>, greater<vec> >q;
    q.push(vec(0,0));
    while(!q.empty()) {
        vec e=q.top();
        q.pop();
        int id=e.first;
        int cost=e.second;
        if(d[id]<cost) continue;
        for(int i=0, an=adj[i].size(); i<an; i++) {
            int adj_id=adj[id][i].first;
            int adj_cost=adj[id][i].second;
            if(d[adj_id] <= adj_cost) continue;
            d[adj_id]=adj_cost;
            q.push(vec(adj_id, adj_cost));
        }
    }
    for(int i=0; i<n; i++) cout<<i<<' '<<d[i]<<'\n';
    return 0;
}

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

using namespace std;


struct edge {
    int src;
    int dst;
    int weight;

    edge(int src, int dst, int w) : src(src), dst(dst), weight(w) {}
};

bool operator < (const edge &a, const edge &b) {
  return a.weight > b.weight;
}


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

    vector<vector<pair<int, int>>> G(n);
    for (int i = 0; i < n; ++i) {
        int u, k;
        cin >> u >> k;

        for (int j = 0; j < k; ++j) {
            int v, c;
            cin >> v >> c;
            G[u].emplace_back(v, c);
        }
    }

    // Dijkstra's algorithm (with pritority queue)
    vector<int> d(n, -1);
    vector<bool> visited(n, false);
    priority_queue<edge> Q;

    Q.emplace(-1, 0, 0);
    while (!Q.empty()) {
        auto e = Q.top(); Q.pop();
        if (visited[e.dst])
            continue;
        d[e.dst] = e.weight;
        visited[e.dst] = true;

        for (auto& x : G[e.dst]) {
            if (visited[x.first])
                continue;
            int w = x.second + d[e.dst];
            Q.emplace(e.dst, x.first, w);
        }
    }

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

    return 0;
}

C++: #include <iostream>
using namespace std;

const int MAX = 100;
const int INFINITY = 2 << 21;
int n;
int G[MAX][MAX];
int distances[MAX];
int states[MAX];

void dijkstra() {
  int id = 0;
  distances[id] = 0;

  while (1) {
    int min = INFINITY;

    for (int i = 0; i < n; i++) {
      if (states[i] == 0 && distances[i] < min) {
        min = distances[i];
        id = i;
      }
    }

    if (min == INFINITY) break;

    for (int i = 0; i < n; i++) {
      if (states[i] != 0 || G[id][i] == -1) continue;
      if (G[id][i] < distances[i]) {
        distances[i] = distances[id]+ G[id][i];
      }
    }

    states[id] = 1;
  }

  for (int i = 0; i < n; i++) {
    cout << i << " " << (distances[i] == INFINITY ? -1 : distances[i]) << endl;
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;

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

  int u, k, v, c;
  for (int i = 0; i < n; i++) {
    distances[i] = INFINITY;
    states[i] = 0;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      cin >> v >> c;
      G[i][v] = c;
    }
  }

  dijkstra();

  return 0;
}

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

using namespace std;

#define MAX_V 10000
#define INF 1e9

struct edge{ int to,cost; };
typedef pair<int,int> P;

int V;
vector<edge> G[MAX_V];
int dist[MAX_V];

void dijkstra(){
  priority_queue<P, vector<P>, greater<P> > Q;
  fill(dist,dist+V,INF);
  dist[0] = 0;
  Q.push(P(0,0));

  while(!Q.empty()){
    P p = Q.top(); Q.pop();
    int v = p.second;

    if(dist[v] < p.first){
      continue;
    }

    for(int i = 0 ; i < (int)G[v].size() ; i++){
      edge e = G[v][i];
      
      if(dist[e.to] > dist[v] + e.cost){
	dist[e.to] = dist[v] + e.cost;
	Q.push(P(dist[e.to],e.to));
      }
    }

  }
}

int main(){
  cin >> V;
 
  for(int i = 0 ; i < V ; i++){
    int u,k;

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

      cin >> v >> c;

      edge e = {v,c};
      G[u].push_back(e);
    }
  }

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

  return 0;
}