Go: package main

import (
	"bufio"
	"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
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

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

C++: #include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

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

	int n;
	cin >> n;

	vector<vector<pair<int, int>>> graph(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;
			graph[u].emplace_back(v, c);
		}
	}

	vector<int> dist(n, INF);
	dist[0] = 0;
	priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
	pq.emplace(0, 0);

	while (!pq.empty()) {
		pair<int, int> p = pq.top(); pq.pop();
		if (dist[p.first] < p.second) {
			continue;
		}

		for (auto e : graph[p.first]) {
			if (dist[e.first] > dist[p.first] + e.second) {
				dist[e.first] = dist[p.first] + e.second;
				pq.emplace(e.first, dist[e.first]);
			}
		}
	}

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

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

const int INF = LONG_LONG_MAX;
typedef pair<int, int> P;
#define int long long

struct edge {int to, cost;};

/*
[input]
const vector<vector<edge>> &graph : ??\?????°??????
int s : ?§????
int g : ??????
n*/
int dijkstra(const vector<vector<edge>> &graph, int s, int g ) {
  // ????????????????±?????????????????????????
  vector<int> d(graph.size(), INF);
  // ????§?????????????????????????0????????????
  d[s] = 0;
  // ??????????????????now
  set<P> now;
  // ????§?????????????now????????\
  now.insert(P(0, s));
  
  // now????????????????????§
  while(!now.empty()) {
    // ?????¨?????????????????????pos???????´?
    int pos = now.begin()->second;
    // ?????¨??????????????????????????????????±???????????????????????????????
    if (pos == g) {
      for(int i = 0; i <= g; i++) {
        cout << i << " " << d[i] << endl;
      }
      return INF;
    }
    // now????????¢?´¢?????????????¶????
    now.erase(now.begin());
    // ?????¨??????????????¨???????????¢?´¢
    for(auto ed: graph[pos]) {
      // ??\?¶??????????????????????????????????????????¨??????????????§????????????
      // ??¨??\?¶?????????§?????¨????????????????????????????????§???????????°
      if(d[ed.to] > d[pos] + ed.cost) {
        // now????????\?¶?????????????????±????????????????????????????
        now.erase(P(d[ed.to], ed.to));
        d[ed.to] = d[pos] + ed.cost;
        now.insert(P(d[ed.to], ed.to));
      }
    }
  }
  return INF;
}
  
signed main() {
  int num;
  cin >> num;
  vector<vector<edge>> graph(num, vector<edge>());
  int f, n, k, v, c;
  for(int i = 0; i < num; i++) {
    cin >> f >> k;
	if(k == 0) continue;
    for(int j = 0; j < k; j++) {
      cin >> v >> c;
      graph[f].push_back(edge{v, c});
      graph[v].push_back(edge{f, c});
    }
  }
  dijkstra(graph, 0, num - 1);
  return 0;
}

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;
}