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<iostream>
#include<vector>
#include<queue>
#define INF 1000000000

using namespace std;

struct vEdge {
	int adj;
	vector<int> weight;
	vector<int> tovtx;
	vEdge() {}

	void setadj(int a) { adj = a; }

	void setnum(int w, int n2) {
		weight.push_back(w); tovtx.push_back(n2);
	}
};

void dijkstra0(const vector<vEdge>& vedge, vector<int>& cost) {
	int mindex, min, temp, v,w, size = vedge.size(), count = 1;
	vector<bool> optimum(size, false);
	queue<int> qdata;
	cost.at(0) = 0; optimum.at(0) = true;

	while (count < size) {
		mindex = -1; min = INF;
		for (int i = 0; i < size; i++) if (optimum.at(i)) {
			for (int j = 0; j < vedge.at(i).adj;j++){
				v = vedge.at(i).tovtx.at(j);
				if (!optimum.at(v)) {
					w = vedge.at(i).weight.at(j);
					temp = cost.at(i) + w;
					if (temp < min) {
						min = temp;
						mindex = v;
					}
					if (temp < cost.at(v)) cost.at(v) = temp;
				}
			}
		}
		optimum.at(mindex) = true;
		count++;
	}

}

int main(void) {
	int size, num, adj, w, n2;
	cin >> size;

	vector<int> cost(size, INF);
	vector<vEdge> vedge(size);

	for (int i = 0; i < size; i++) {
		cin >> num >> adj;
		vedge.at(num).setadj(adj);
		for (int j = 0; j < adj; j++) {
			cin >> n2 >> w;
			vedge.at(num).setnum(w, n2);
		}
	}
	dijkstra0(vedge, cost);

	for (int i = 0; i < size; i++) cout << i << " " << cost.at(i) << endl;
	return 0;

}

C++: #include<bits/stdc++.h>
#define INF 0x3f3f3f3f 
using namespace std;
const int maxn = 11111;
int n, m;
struct edge
{
	int v, cost;
	edge(int _v=0,int _cost=0):v(_v),cost(_cost){}
};
vector<edge> g[maxn];
bool book[maxn];
int dis[maxn];
void myinit()
{
	memset(book, 0, sizeof(book));
	for (int i = 0; i < maxn; i++)
	{
		g[i].clear();
	}
	fill(dis, dis + maxn,INF);
}
void SPFA(int s)
{
	queue<int> q;
	q.push(s);
	book[s] = 1;//加入队列并标记 
	while (!q.empty())
	{
		int temp = q.front();
		q.pop();
		book[temp] = 0;//弹出队列并取消标记 
		for (int i = 0; i < g[temp].size(); i++)
		{
			if (g[temp][i].cost + dis[temp] < dis[g[temp][i].v])//比较 
			{
				dis[g[temp][i].v] = g[temp][i].cost + dis[temp];//更新路径 
				if (!book[g[temp][i].v])//若该点不在队列 
				{
					q.push(g[temp][i].v);
					book[g[temp][i].v] = 1;
				}
			}
		}
	}
}
void addedge(int u, int v, int w)
{
	g[u].push_back(edge(v, w));
}
int main()

{
	cin >> n;
	m = 0;
	myinit();
	for (int i = 0;i < n;i++)
	{
		int ve, en, co;
		int k;
		cin >> ve >> k;
		for (int j = 0;j < k;j++)
		{
			cin >> en >> co;
			addedge(ve, en, co);
		}
	}
	dis[0] = 0;
	SPFA(0);
	for (int i = 0;i < n;i++)
		cout << i << " " << dis[i] << endl;
	return 0;
}

C++: #include <iostream>
#include <algorithm> 
#include <cstdio>
#include <cstring>
using namespace std;

#define INF 1000000 //极大的数 
const int N = 1009;

int d[N],v[N],w[N][N]; //d[i]为起始点到i的最短路径   v[i]为标记数组    w[x][y]表示边(x,y)的长度. 
int main(){
	int n,m,a,b,c,beg,end;
	while((scanf("%d",&n))!=EOF){
		memset(w,0,sizeof(w));
		memset(d,0,sizeof(d));
		memset(v,0,sizeof(v));
		for(int i=0;i<n;i++){
			scanf("%d%d",&a,&m);
			for(int j=0;j<m;j++){
				scanf("%d%d",&b,&c);
				w[i][b] = w[b][i] = c;
			}
		}
		for(int i=0;i<n;i++) d[i] = (i==0?0:INF);
		for(int i=0;i<n;i++){
			int x,a = INF; 
			for(int y=0;y<n;y++)
				if(!v[y]&&d[y]<=a) a = d[x=y];
				v[x] = 1;
		for(int j=0; j<n; j++)
                if(!v[j] && w[x][j] && d[x]+w[x][j] < d[j])
                    d[j] = d[x]+w[x][j];
		}
		for(int i=0;i<n;i++){
			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 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>
int main(){
  int u,k,C,V,A[1000][1000],D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){     std::cin >> u >> k;
    for(int j=0;j<k;j++){   std::cin >> V >> C;
      D[u][V] = C;}}
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}

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

#define NIL -1
#define MAX (1 << 24)

struct Node {
	int dis = MAX;
	bool flag = false;
	vector<int> d;
	vector<int> id;
};

void dijkstra(vector<Node>& u)
{
	u[0].dis = 0;

	while (1)
	{
		int mini = MAX;
		int n;
		for (int i = 0; i < u.size(); i++)
		{
			if (!u[i].flag && u[i].dis < mini) {
				mini = u[i].dis;
				n = i;
			}
		}

		if (mini == MAX) return;
		u[n].flag = true;

		for (int i = 0; i < u[n].id.size(); i++)
		{
			if (u[u[n].id[i]].flag) continue;
			if ((u[n].dis + u[n].d[i]) < u[u[n].id[i]].dis) {
				u[u[n].id[i]].dis = u[n].dis + u[n].d[i];
			}
		}
	}
}

int main(void)
{
	int i, N, v, k, c, x;
	cin >> N;
	vector<Node> u(N);
	for (i = 0; i < N; i++)
	{
		cin >> v >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> x >> c;
			u[v].id.push_back(x);
			u[v].d.push_back(c);
		}
	}

	
	dijkstra(u);

	for (i = 0; i < N; i++) cout << i << " " << u[i].dis << endl;

	return 0;
}