Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

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

#define ll long long
#define vvi vector<vector<int>>
#define vec vector
#define pq priority_queue
#define all(v) (v).begin(), (v).end()
#define uniqueV(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define rep(i, n) for (int (i) = (0); (i) < (n); ++(i))
#define repp(i, m, n) for (int (i) = (m); (i) < (n); ++(i))
#define debug(x) cerr << #x << ": " << x << endl;
#define debug2(x, y) cerr<<"("<<#x<<", "<<#y<<") = "<<"("<<x<<", "<<y<<")"<<endl;
#define debug3(x, y, z) cerr<<"("<<#x<<", "<<#y<<", "<<#z<<") = "<<"("<<x<<", "<<y<<", "<<z<<")"<<endl;
#define debugB(x, y) cerr<<#x<<": "<<bitset<y>(x) << endl;
#define line() cerr << "---------------" << endl;

const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const double PI = 3.14159265358979323846;

template<typename T>
void printA(vector<T> &printArray, char between = ' ') {
   int paSize = printArray.size();
   for (int i = 0; i < paSize; i++) { cerr << printArray[i] << between;}
   if (between != '\n') {cerr << endl;}
}

// ------------------------------------------------------------------------------------------

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

const int INF = 1e8;
int n;
vec<vec<edge>> G;
int d[111];

void dijkstra(int s) {
   priority_queue<P, vec<P>, greater<P>> Q;
   fill(d, d + n, INF);
   d[s] = 0;
   Q.push({0, s});

   while (Q.size()) {
      P p = Q.top(); Q.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;
            Q.push({d[e.to], e.to});
         }
      }
   }
}

int main() {
   cin >> n;
   G = vec<vec<edge>>(n);
   rep (i, n) {
      int u, k;
      cin >> u >> k;
      rep (j, k) {
         int v, c;
         cin >> v >> c;
         G[u].push_back({v, c});
      }
   }

   dijkstra(0);

   rep (i, n) {
      printf("%d %d\n", i, d[i]);
   }

   return 0;
}

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

const int inf = 1<<29;
int n;
vector<pair<int, int>> G[110];
vector<int> d(110, inf);

void dijkstra(int s){
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> qu;
    d[s] = 0;
    qu.push(make_pair(0, s));

    while(!qu.empty()){
        pair<int, int> p = qu.top(); qu.pop();
        if(d[p.second] < p.first) continue;
        for(auto e:G[p.second]){
            if(d[e.second] > p.first+e.first){
                d[e.second] = p.first+e.first;
                qu.push(make_pair(d[e.second], e.second));
            }
        }
    }
}

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

    dijkstra(0);
    for(int i=0; i<n; ++i){
        cout << i << ' ' << d[i] << '\n';
    }

    return 0;

}

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

using WNode = std::pair<uint32_t, uint32_t>;
using WGraph = std::vector<std::vector<WNode>>;

int main() {
  uint32_t N = 0;
  std::cin >> N;
  WGraph G(N);
  for (size_t i = 0; i < N; i++) {
    uint32_t K = 0;
    std::cin >> i >> K;
    for (size_t j = 0; j < K; j++) {
      uint32_t node = 0, cost = 0;
      std::cin >> node >> cost;
      G[i].push_back({node, cost});
    }
  }

  const uint32_t start = 0;
  std::vector<uint32_t> min_cost(N, -1);
  min_cost[start] = 0;
  std::vector<uint32_t> prev_node(N, -1);
  prev_node[start] = start;
  std::vector<bool> visit(N, false);
  for (size_t i = 0; i < N; i++) {
    uint32_t current = 0, min = -1;
    for (size_t j = 0; j < N; j++) {
      if (visit[j] || min_cost[j] >= min) continue;
      min = min_cost[j];
      current = j;
    }
    visit[current] = true;

    for (auto &&g : G[current]) {
      if (min_cost[g.first] <= g.second + min_cost[current]) continue;
      min_cost[g.first] = g.second + min_cost[current];
      prev_node[g.first] = current;
    }
  }

  for (size_t i = 0; i < N; i++) {
    std::cout << i << " " << min_cost[i] << std::endl;
  }

  return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX =100;
static const int INFTY = (1<<21);
static const int WHITE =0;
static const int GRAY = 1;
static const int BLACK = 2;
int n,M[MAX][MAX];
void dijkstra(){
  int minv;
  int d[MAX],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(minv>d[i] && color[i]!=BLACK){
        u=i;
        minv=d[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]) << endl;
  }
}

int main(){
  cin >> n;
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      M[i][j]=INFTY;
    }
  }
  int k,c,u,v;
  for(int i=0;i<n;i++){
       cin >> u >>k;
    for(int j=0;j<k;j++){
      cin >> v >>c;
      M[u][v]=c;
    }
  }
  dijkstra();
  return 0;
}