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()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	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 i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: // clang-format off
#include <bits/stdc++.h>
#define int long long
#define main signed main()
#define loop(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) loop(i, 0, n)
#define forever while (true)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define prec(n) fixed << setprecision(n)
template<typename A> using V = std::vector<A>;
template<typename A> using F = std::function<A>;
template<typename A, typename B> using P = std::pair<A, B>;
using pii = P<int, int>;
using vi = V<int>;
using vd = V<double>;
using vs = V<std::string>;
using vpii = V<pii>;
using vvi = V<vi>;
using vvpii = V<vpii>;
constexpr int INF = sizeof(int) == sizeof(long long) ? 1000000000000000000LL : 1000000000;
constexpr int MOD = 1000000007;
constexpr double PI = acos(-1);
template<typename A, typename B> bool cmin(A &a, const B &b) { return a > b ? (a = b, true) : false; }
template<typename A, typename B> bool cmax(A &a, const B &b) { return a < b ? (a = b, true) : false; }
template<typename T> std::istream &operator>>(std::istream &is, std::vector<T> &v) { for (T &x : v) is >> x; return is; }
using namespace std;
// clang-format on

using Weight = int;
struct Edge {
  int src, dst;
  Weight weight;
  Edge(const int &s = 0, const int &d = 0, const Weight &w = 0) : src(s), dst(d), weight(w) {}
};

using Edges = std::vector<Edge>;
using Array = std::vector<Weight>;
using Matrix = std::vector<Array>;

class Graph {
  std::vector<Edges> g;

public:
  Graph(const int &size = 0) : g(size) {}

  void addArc(const int &src, const int &dst, const Weight &w = 1) { g[src].emplace_back(src, dst, w); }

  void addEdge(const int &node1, const int &node2, const Weight &w = 1) {
    addArc(node1, node2, w);
    addArc(node2, node1, w);
  }

  const Edges &operator[](const int &i) const { return g[i]; }

  Graph toRootedTree(int r);
  std::pair<std::vector<Weight>, std::vector<int>> dijkstra(const int &src, const int &inf);
  Matrix warshallFloyd(const int &inf);
  std::pair<Weight, Edges> prim(const int &r);
  template<typename UnionFind> std::pair<Weight, Edges> kruskal();
  Weight solveTSP(const int &inf);
};

std::pair<std::vector<Weight>, std::vector<int>> Graph::dijkstra(const int &src, const int &inf = std::numeric_limits<Weight>::max() / 8) {
  using state = std::pair<Weight, int>;
  std::priority_queue<state, std::vector<state>, std::greater<state>> q;
  std::vector<Weight> dist(g.size(), inf);
  std::vector<int> via(g.size());
  dist[src] = 0;
  q.emplace(0, src);
  while (q.size()) {
    Weight d;
    int v;
    std::tie(d, v) = q.top();
    q.pop();
    if (dist[v] < d) continue;
    for (auto &e : g[v]) {
      if (cmin(dist[e.dst], dist[v] + e.weight)) {
        via[e.dst] = v;
        q.emplace(dist[e.dst], e.dst);
      }
    }
  }
  return {dist, via};
}

main {
  int n;
  cin >> n;
  Graph g(n);
  rep(_, n) {
    int u, k;
    cin >> u >> k;
    while (k--) {
      int v, c;
      cin >> v >> c;
      g.addArc(u, v, c);
    }
  }
  vi d = g.dijkstra(0).first;
  rep(i, n) cout << i << ' ' << d[i] << endl;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1 << 20);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> adj[MAX];

void dijkstra() {
	priority_queue<pair<int, int>> PQ;
	int color[MAX];
	int d[MAX];
	for (int i = 0; i < n; i++) {
		d[i] = INFTY;
		color[i] = WHITE;
	}

	d[0] = 0;
	PQ.push(make_pair(0, 0));
	color[0] = GRAY;

	while (!PQ.empty()) {
		pair<int, int> f = PQ.top(); PQ.pop();
		int u = f.second;
		color[u] = BLACK;

		if (d[u] < f.first*(-1)) continue;

		for (unsigned int j = 0; j < adj[u].size(); j++) {
			int v = adj[u][j].first;
			if (color[v] == BLACK) 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] = GRAY;
			}
		}
	}

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

int main() {
	int k, u, v, c;

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

	dijkstra();

	return 0;
}

C++: #include <iostream>
 using namespace std;
 static const int WHITE = 0;
 static const int GRAY = 1;
 static const int BLACK =2;
 static const int MAX = 100;
 static const int INFTY = (1<<21);
 
 int n,M[MAX][MAX];
 
 void dijks(){
 	int minv;
 	int d[MAX],p[MAX];
 	int color[MAX];
 	for(int i=0;i<n;i++){
 		d[i] = INFTY;
 		color[i] = WHITE;
 	}
 	
 	d[0] = 0;
 	color[0] = GRAY;
 	while(1){
 		minv = INFTY;
 		int u=-1;
 		for(int i=0;i<n;i++){
 			if(color[i]!=BLACK&&d[i]<INFTY){
 				minv = d[i];
 				u=i;
 			}
 		}
 		
 		if(u==-1) break;
 		
 		color[u] = BLACK;
 		
 		for(int v=0;v<n;v++){
 			if(color[v]!=BLACK&&M[u][v]<INFTY){
 				if(d[v]>d[u]+M[u][v]){
 					d[v] = d[u]+M[u][v];
 					color[v] = GRAY;
 				}
 			}
 		}
 	}
 	
 	for(int i=0;i<n;i++){
 		cout<<i<<" "<<(d[i]==INFTY?-1:d[i]);
 	}
 }
 
 int main(){
 	cin>>n;
 	
 	for(int i=0;i<n;i++){
 		for(int j=0;j<n;j++){
 			M[i][j] = INFTY;
 		}
 	}
 	
 	int k,u,c,v;
 	for(int i=0;i<n;i++){
 		cin>>u>>k;
 		for(int j=0;j<k;j++){
 			cin>>c>>v;
 			M[u][c] = v;
 		}
 	}
 	dijks();
 	return 0;
 }