Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
constexpr int MAX = 100;
enum Color { WHITE = 0, GRAY, BLACK };
int n;
vv(int, M, MAX, MAX, INT_MAX);
inline void dijkstra() {
    vi d(MAX, INT_MAX), color(MAX, WHITE);
    d[0] = 0;
    color[0] = GRAY;
    int minv, u;
    while(true) {
        minv = INT_MAX;
        u = -1;
        rep(i, 0, n) {
            if(minv > d[i] && color[i] != BLACK) {
                u = i;
                minv = d[i];
            }
        }
        if(u == -1) break;
        color[u] = BLACK;
        rep(v, 0, n) {
            if(color[v] != BLACK && M[u][v] != INT_MAX && d[v] > d[u] + M[u][v]) {
                d[v] = d[u] + M[u][v];
                color[v] = GRAY;
            }
        }
    }
    rep(i, 0, n) {
        cout << i << " " << d[i] << "\n";
    }
}
int main() {
    cin >> n;
    int u, k, v, c;
    rep(i, 0, n) {
        cin >> u >> k;
        rep(j, 0, k) {
            cin >> v >> c;
            M[u][v] = c;
        }
    }
    dijkstra();
    return 0;
}

C++: #include <cstdio>
#include <algorithm>
#include <queue>
using namespace std;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> adj[100];
int *d;

void dijkstra() {
    priority_queue<pair<int, int>> PQ;
    int d[n], color[n];

    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
        color[n] = WHITE;
    }
    d[0] = 0;
    PQ.push(make_pair(0, 0));

    while (!PQ.empty()) {
        pair<int, int> f = PQ.top();
        PQ.pop();

        int u = f.second;
        color[u] = BLACK;

        if (d[u] < f.first * (-1)) { continue; }

        for (int j = 0; j < adj[u].size(); j++) {
            int v = adj[u][j].first;
            if (color[v] == BLACK) { continue; }
            if (d[u] + adj[u][j].second < d[v]) {
                d[v] = d[u] + adj[u][j].second;
                // printf("d[%d] = %d\n", v, d[v]);
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;
            }
        }
    }
    
    for (int i = 0; i < n; i++) {
        printf("%d %d \n", i, d[i]);
    }
}

int main() {
    scanf("%d", &n);

    // adj = new vector<pair<int, int>>[n];

    for (int i = 0; i < n; i++) {
        int u, k;
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; j++) {
            int v, c;
            scanf("%d %d", &v, &c);
            adj[u].push_back(make_pair(v, c));
        }
    }

    dijkstra();

    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 GRRAY = 1;
static const int BLACK = 2;

int n;
int M[100][100];

int dijkstra(){
  int u,minv,i,v;
  int d[MAX],color[MAX];

  for(i=0;i<n;i++){
    d[i]=INFTY;
    color[i]=WHITE;
  }

  d[0]=0;
  color[0]=GRRAY;
  while(1){
    minv=INFTY;
    u=-1;
    for(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(v=0;v<n;v++){
      if(M[u][v] != INFTY && color[v] != BLACK){
	if(d[v]>d[u]+M[u][v]){
	  d[v]=d[u]+M[u][v];
	  color[v]=GRRAY;
	}
      }
    }
  }
    for(i=0;i<n;i++){
      cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}

int main(){
  int i,j;

  cin >> n;
 
 for(i=0;i<n;i++){
    for(j=0;j<n;j++){
      M[i][j]=INFTY;
    }
  }

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

C++: #include <iostream>
#include<cstdio>
#include <algorithm>
using namespace std;
typedef long long ll;
ll dp[105][105];
const ll INF = 0x3f3f3f3f;
int main()
{
    int n,i,m,j,a,b,k;
    scanf("%d",&n);
    for(i = 0;i < n;i++)
        for(j = 0;j < n;j++)
            dp[i][j] = INF;
    dp[0][0] = 0;
    for(j = 0;j < n;j++)
    {
        cin >> i >> m;
        while(m--)
        {
            cin >> a ;
            cin >> dp[i][a];
        }
    }
    for(k = 0;k < n;k++)
        for(i = 0;i < n;i++)
            for(j = 0;j < n;j++)
                dp[i][j] = min(dp[i][j],dp[i][k]+dp[k][j]);
    for(i = 0;i < n;i++)
        cout << i << ' ' << dp[0][i] << endl;
    return 0;
}