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>
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];

int 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;
    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 <limits.h>
#include <vector>

using namespace std;

struct Node {
    int cost = INT_MAX;
    int color = 0;
    vector<int> next_node;
    vector<int> len_cost;
} node[100];

int main() {
    int n, id, k;

    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> id >> k;
        node[id].next_node.resize(k);
        node[id].len_cost.resize(k);
        for (int j = 0; j < k; j++) {
            cin >> node[id].next_node[j] >> node[id].len_cost[j];
        }
    }

    int size1, size2;
    vector<int> vec;
    node[0].cost = 0;
    node[0].color = 1;
    vec.push_back(0);
    while (1) {
        size1 = vec.size();
        if (size1 == n) {
            break;
        }
        for (int i = 0; i < size1; i++) {
            size2 = node[vec[i]].next_node.size();
            for (int j = 0; j < size2; j++) {
                if (node[node[vec[i]].next_node[j]].cost > node[vec[i]].cost + node[vec[i]].len_cost[j]) {
                    node[node[vec[i]].next_node[j]].cost = node[vec[i]].cost + node[vec[i]].len_cost[j];
                }
            }
        }
        int min = INT_MAX, mini;
        for (int i = 0; i < size1; i++) {
            size2 = node[vec[i]].next_node.size();
            for (int j = 0; j < size2; j++) {
                if (min > node[node[vec[i]].next_node[j]].cost && node[node[vec[i]].next_node[j]].color == 0) {
                    min = node[node[vec[i]].next_node[j]].cost;
                    mini = node[vec[i]].next_node[j];
                }
            }
        }
        vec.push_back(mini);
        node[mini].color = 1;
    }

    for (int i = 0; i < n; i++) {
        cout << i << " " << node[i].cost << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <set>
#include <cstring>
#include <cmath>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i, k, n) for (int i = (int)(k); i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rREP(i, k, n) for (int i = (int)(n)-1; i >= k; i--)

#define debug(x) cerr<<#x<<": "<<x<<'\n'

#define fi first
#define se second

#define vi vector<int>
#define pb push_back
#define mp make_pair

#define pcnt __builtin_popcount

typedef long long ll;

const int inf = 100100100;
const int MOD = 998244353;
const double EPS = 1e-9;

vector<vector<pair<int,int> > > G(110);

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    rep(i,n){
      int u,k;
      cin >> u >> k;
      rep(j,k){
        int v,c;
        cin >> v >> c;
        G[u].push_back(mp(v,c));
        G[v].push_back(mp(u,c));
      }
    }
    int d[110] = {};
    rep(i,110) d[i] = inf;
    d[0] = 0;
    while(true){
        bool update = false;
        rep(i,n){
          for(auto o : G[i]){
            if(d[o.fi] > d[i]+o.se){
                d[o.fi] = d[i]+o.se;
                update = true;
            }
          }
        }
        if(!update) break;
    }
    rep(i,n) cout << i << " " << d[i] << endl;
    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define INF 1<<30
using namespace std;
typedef unsigned long long ull;
int n;
int A[1000][1000];
bool used[1000];
ull D[1000][1000];
 
void Init(int f){
  for(int i=0;i<f;i++){
    for(int j=0;j<f;j++)D[i][j] = INF;
  }
 
}
 
int main(){
  scanf("%d",&n);
  int u,k,C,V;
  Init(n);
  
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);    
      for(int j=0;j<k;j++){
    scanf("%d %d",&V,&C);
    D[u][V] = C;
    D[V][u] = 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] = min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++){
    cout << i << " " << D[0][i] << endl;
  }
 
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const int Inf = 1e9;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;

const int N = 10001;

using P = pair<int, int>;

int n;

struct edge {
    int to;
    int cost;
};

vector<int> dist(N, Inf);
vector<edge> g[N];

void dijkstra(int s) {
    dist[s] = 0;
    priority_queue<P, vector<P>, greater<P> > pq;
    pq.push(P(0, s));

    while (!pq.empty()) {
        P p = pq.top();
        pq.pop();
        int v = p.second;
        if (dist[v] < p.first) continue;

        rep (i, g[v].size()) {
            edge e = g[v][i];
            if (dist[e.to] > dist[v] + e.cost) {
                dist[e.to] = dist[v] + e.cost;
                pq.push(P(dist[e.to], e.to));
            }
        }
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    cin >> n;
    rep (i, n) {
        int u, k;
        cin >> u >> k;
        rep (j, k) {
            int v, c;
            cin >> v >> c;
            edge e = {v, c};
            g[u].push_back(e);
        }
    }
    dijkstra(0);
    rep (i, n) {
        cout << i << " " << dist[i] << endl;
    }
    
    return 0;
}