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 <cstdint>
#include <vector>

using namespace std;

#define GRAPH_SIZE 100
#define WEIGHT_MAX (1 << 21)

enum state_t {
  WHITE,
  GRAY,
  BLACK,
};

static uint32_t graph[GRAPH_SIZE][GRAPH_SIZE];
static state_t state[GRAPH_SIZE];
static uint32_t dist[GRAPH_SIZE];

size_t single_source_shotest_path(size_t num)
{
  size_t cost = 0;

  for (uint32_t i = 0; i < num; i++) {
    state[i] = WHITE;
    dist[i] = WEIGHT_MAX;
  }

  state[0] = GRAY;
  dist[0] = 0;

  while (true) {
    size_t minimum_cost = WEIGHT_MAX;
    uint32_t to = 0;
    for (uint32_t i = 0; i < num; i++) {
      if ((dist[i] < minimum_cost) && (state[i] != BLACK)) {
        minimum_cost = dist[i];
        to = i;
      }
    }

    if (minimum_cost == WEIGHT_MAX) break;

    cost += minimum_cost;
    state[to] = BLACK;

    for (uint32_t i = 0; i < num; i++) {
      if (((dist[to] + graph[to][i]) < dist[i]) && state[i] != BLACK) {
        state[i] = GRAY;
        dist[i] = dist[to] + graph[to][i];
      }
    }
  }

  return cost;
}

#include <iostream>

int32_t main()
{
  uint32_t num;
  cin >> num;

  for (uint32_t i = 0; i < num; i++) {
    for (uint32_t j = 0; j < num; j++) {
      graph[i][j] = WEIGHT_MAX;
    }
  }

  for (uint32_t i = 0; i < num; i++) {
    uint32_t index, len;
    cin >> index >> len;
    for (uint32_t j = 0; j < len; j++) {
      uint32_t v, c;
      cin >> v >> c;
      graph[index][v] = c;
    }
  }

  single_source_shotest_path(num);

  for (uint32_t i = 0; i < num; i++) {
    cout << i << " " << dist[i] << 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;
        }
       }
     }
  }
    if(u == -1) break;
    color[u] = BLACK;
   for(int v = 0; v < n; v++){
    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,v,c,u;
 for(int i = 0;i < n; i++){
  cin >> u >>c;
  M[u][v] = c;
  }
 }
  dijkstra();
   return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define WHITE 0
#define VISITED 1
#define CANDIDATE 2

int dks(vvi &a, vi &d, vi &s, vi &p) {
  int total = 0, n = (int)a.size();
  while (true) {
    int min_cost = INT_MAX, u;
    rep(i, n) {
      if (s[i] != VISITED && d[i] < min_cost) {
        min_cost = d[i];
        u = i;
      }
    }

    if (min_cost == INT_MAX) break;

    s[u] = VISITED;
    if (p[u] != -1) total += a[p[u]][u];

    rep(v, n) {
      if (s[v] != VISITED && a[u][v] != -1) {
        if (d[u] + a[u][v] < d[v]) {
          d[v] = d[u] + a[u][v];
          p[v] = u;
          s[v] = CANDIDATE;
        }
      }
    }
  }
  
  return total;
}

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

  vvi g(n, vi(n, -1));
  rep(i, n) {
    int u, k;
    cin >> u >> k;

    rep(j, k) {
      int v, c;
      cin >> v >> c;

      g[u][v] = c;
    }
  }
  
  vi d(n, INT_MAX), s(n, WHITE), p(n, -1);
  d[0] = 0;
  
  dks(g, d, s, p);
  
  rep(i, n) printf("%d %d\n", i, d[i]);
}

C++: #include <iostream>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1<<21);
static const int WHITH = 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] = WHITH;
  }

  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;
}