Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include <bits/stdc++.h>
#define MAX_E 1000000
#define MAX_V 100000
#define INF 1e9
using namespace std;
/*??????????????????????????? O(V*E)*/

//??????from????????????to???????????????cost??????
struct edge{int from, to, cost;};
edge es[MAX_E]; //???
int d[MAX_V];   //???????????¢
int V,E;        //V???????????°???E????????°

//s???????????????????????????????????????????????¢????±???????.
void Bellman_Ford(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;
  }
}

//true??????????????????????????¨??????
bool find_negative_loop(){
  memset(d,0,sizeof(d));

  for(int i=0; i<V ;i++){
    for(int j=0; j<E ;j++){
      edge e = es[j];
      if(d[e.to] > d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	
	//n??????????????´??°???????????????????????????????????¨?????????
	if(i == V-1) return true;
      }
    }
  }
  return false;
}

int main(){
  cin>>V;
  for(int i=0;i<V;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0,v,c;j<k;j++){
      cin>>v>>c;
      es[E++]=(edge){u,v,c};
      es[E++]=(edge){v,u,c};
  }
  }
  
  for(int i=0;i<V;i++){
    Bellman_Ford(i);
    cout <<i<<" "<<d[0]<<endl;
  }
}

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;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#define MAX_V 100
#define INF 1e9
using namespace std;
int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;
void dijkstra(int s) {
	for (int i = 0; i < V; i++) {
		d[i] = INF;
		used[i] = false;
	}
	d[s] = 0;
	while (true) {
		int v = -1;
		for (int u = 0; u < V; u++) {
			if (!used[u] && ((v == -1) || d[u] < d[v])) {
				v = u;
			}
		}
		//全ての頂点が到達済み
		if (v == -1) {
			break;
		}
		//集合に新たに頂点を追加
		used[v] = true;
		for (int u = 0; u < V; u++) {
			if (cost[v][u] != -1) {
				d[u] = min(d[u], d[v] + cost[v][u]);
			}
		}
	}
}

int main() {
	for (int i = 0; i < MAX_V; i++) {
		for (int j = 0; j < MAX_V; j++) {
			cost[i][j] = -1;
		}
	}
	cin >> V;
	for (int i = 0; i < V; i++) {
		int u;
		cin >> u;
		int k;
		cin >> k;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			int c;
			cin >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);

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

C++: #include <stdio.h>
#include <iostream>
#include <queue>
using namespace std;

class Vertice;
class Edge;

class Vertice{
private:
	int id;
	int edge_num;
	int *vertice_id_list;
	Edge **edges;
	bool flag_fixed;
	int distance_min;
public:
	Vertice(int id, int edge_num_max);
	~Vertice(){ delete[] edges, vertice_id_list; }
	int getDistanceMin() const { return distance_min; }
	void addEdge(int vertice_id, Edge *edge);
	void addVertices(Vertice *vertices[]);
	void setDistance(int d);
	void serveDistance();
	void setFlagFixed(){ flag_fixed = true; }
};

class Edge{
private:
	int distance;
	Vertice *vertice;
public:
	Edge(int distance){ this->distance = distance; }
	void addVertice(Vertice *vertice){ this->vertice = vertice; }
	void setDistance(int distance){ vertice->setDistance(distance + this->distance); }
};

struct verticeComp {
	bool operator()(const Vertice *v1, const Vertice *v2)
	{
		return v1->getDistanceMin() > v2->getDistanceMin();
	}
};

priority_queue<Vertice*, vector<Vertice*>, verticeComp> PQ; 

Vertice::Vertice(int id, int edge_num_max)
{
	this->id = id;
	edge_num = 0;
	vertice_id_list = new int[edge_num_max];
	edges = new Edge*[edge_num_max];
	flag_fixed = false;
	distance_min = 1000000;
}

void Vertice::addEdge(int vertice_id, Edge *edge)
{
	edges[edge_num] = edge;
	vertice_id_list[edge_num] = vertice_id;
	edge_num++;
}

void Vertice::addVertices(Vertice *vertices[])
{
	for (int i = 0; i < edge_num; i++) {
		edges[i]->addVertice(vertices[vertice_id_list[i]]);
	}
}

void Vertice::setDistance(int d)
{
	if (flag_fixed) return;
	if (d < distance_min) distance_min = d;
	PQ.push(this);
}

void Vertice::serveDistance()
{
	for (int i = 0; i < edge_num; i++) {
		edges[i]->setDistance(distance_min);
	}
	if (PQ.empty()) return;
	Vertice *fixed_vertice = PQ.top();
	PQ.pop();
	fixed_vertice->setFlagFixed();
	fixed_vertice->serveDistance();
}

int main(void)
{
	Vertice **vertices;

	int n;
	cin >> n;
	vertices = new Vertice*[n];cout << "wa1" << endl;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		vertices[u] = new Vertice(u, k);
		for (int j = 0; j < k; j++) {
			int v, c;
			cin >> v >> c;
			vertices[u]->addEdge(v, new Edge(c));
		}
	}cout << "wa2" << endl;

	for (int i = 0; i < n; i++) {
		vertices[i]->addVertices(vertices);
	}cout << "wa3" << endl;

	vertices[0]->setDistance(0);cout << "wa4" << endl;
	vertices[0]->setFlagFixed();cout << "wa41" << endl;
	PQ.pop();cout << "wa42" << endl;
	vertices[0]->serveDistance();cout << "wa5" << endl;

	for (int i = 0; i < n; i++) {
		cout << i << " ";
		cout << vertices[i]->getDistanceMin() << endl;
	}cout << "wa6" << endl;

	return 0;
}