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 <iostream>
#include <vector>
using namespace std;

typedef struct NODE {
    int id;
    int degree;
    int min_cost;
    bool done;
    vector<int> adj_n;
    vector<int> cost_to_n;
} node;

node **nodes;
int n;

node *gen_node(int id, int degree, vector<int> adj_n, vector<int> cost_to_n) {
    node *p = (node *)malloc(sizeof(node));
    p->id = id;
    p->degree = degree;
    if (id != 0) {
        p->min_cost = 100010;
    } else {
        p->min_cost = 0;
    }

    p->done = false;
    p->adj_n = adj_n;
    p->cost_to_n = cost_to_n;
    return p;
}

void solve() {
    for (int i = 0; i < n; i++) {
        node *src = (node *)malloc(sizeof(node));
        src = nodes[i];
        for (int j = 0; j < src->degree; j++) {
            node *dst = (node *)malloc(sizeof(node));
            dst = nodes[src->adj_n[j]];

            // 最小コストの更新
            //cout << "src: " << src->id << " dst: " << dst->id;
            //cout << " dst's min cost: " << dst->min_cost << " src's cost to dst: " << src->min_cost + src->cost_to_n[j] << endl;
            dst->min_cost = min(dst->min_cost, src->min_cost + src->cost_to_n[j]);

            // // dstの隣接nodeからsrcを消す処理
            // auto itr = find(dst->adj_n.begin(), dst->adj_n.end(), src->id);
            // int erase_index = itr - dst->adj_n.begin();
            // dst->degree--;
            // dst->adj_n.erase(dst->adj_n.begin() + erase_index);
            // dst->cost_to_n.erase(dst->cost_to_n.begin() + erase_index);
        }
    }
}

void print_node() {
    for (int i = 0; i < n; i++) {
        cout << nodes[i]->id << " " << nodes[i]->min_cost << endl;
    }
}

int main() {
    int u, k;
    cin >> n;

    nodes = (node **)malloc(sizeof(node) * n);

    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        vector<int> adj_n;
        vector<int> cost_to_n;

        int node_tmp;
        int cost_tmp;
        for (int j = 0; j < k; j++) {
            cin >> node_tmp >> cost_tmp;
            adj_n.push_back(node_tmp);
            cost_to_n.push_back(cost_tmp);
        }
        node *p = gen_node(u, k, adj_n, cost_to_n);
        nodes[u] = p;
    }

    solve();
    solve();

    print_node();

    return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;
struct edge {int from, to, cost;};
const long long INF = 1000000000;
void bellman_ford(std::vector<edge> & es, std::vector<int> & d, int E, int V, int s) {
  for(int i=0;i<V;i++) d[i] = INF;
  d[s] = 0;
  while(true) {
    bool update = false;
    for(int i=0;i<E;i++) {
      edge e = es[i];
      if(d[e.from] != INF && d[e.to] > d[e.from] + e.cost) {
        d[e.to] = d[e.from] + e.cost;
        update = true;
      }
    }
    if(!update) break;
  }
}
 
int main() {
  int n;
  cin >> n;
  vector<edge> e;
  for(int i=0;i<n;i++) {
    int u, k;
    cin >> u >> k;
    for(int j=0;j<k;j++) {
      int vi, ci;
      cin >> vi >> ci;
      edge ei = {u, vi, ci};
      e.push_back(ei);
    }
  }
  vector<int> d(n);
  bellman_ford(e, d, e.size(), n, 0);
  for(int i=0;i<n;i++) {
    cout << i << " " << d[i] << endl;
  }

}

C++: #include <iostream>
using namespace std;
#define MAX 100
#define INFTY 1<<22
#define WHITE 0
#define GRAY 1
#define BLACK 2

int gMatrix[MAX][MAX];

void dijkstra(int n){
    // 最小の重みを記録する
    int minV;
    int weight[MAX];
    int color[MAX];
    
    for(int i = 0;i < n;++i){
        weight[i] = INFTY;
        color[i] = WHITE;
    }
    // 始点
    weight[0] = 0;
    color[0] = GRAY;
    
    while(1){
        minV = INFTY;
        // 頂点
        int u = -1;
        for(int i = 0;i < n;++i){
            if(minV > weight[i] && color[i] != BLACK){
                u = i;
                minV = weight[i];
            }
        }
        if(u == -1)break;
        color[u] = BLACK;
        
        for(int v = 0;v < n;++v){
            if(color[v] != BLACK && gMatrix[u][v] != INFTY){
                if(weight[v] > weight[u] + gMatrix[u][v]){
                    weight[v] = weight[u] + gMatrix[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }
    // 出力
    for(int i = 0;i < n;++i){
        cout << i << " " << ( weight[i] == INFTY ? -1 : weight[i] ) << endl;
    }
}

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