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 <algorithm>
#include <string>
#include <limits>
#include <queue>
#include <map>
#include <ctime>

using namespace std;

#define rip(i,n,s) for (int i=(s);i<(int)(n);i++)
#define all(a) (a).begin(),(a).end()
typedef pair<long long,int> P;
int main(){
    int n;
    cin >> n;
    vector<vector<P> > da(n,vector<P>(0));
    rip(i,n,0){
        int u,k;
        cin >> u >> k;
        rip(j,k,0){
            long long c;
            int v;
            cin >> v >> c;
            da[u].push_back(make_pair(c,v));
        }
    }
    priority_queue<P,vector<P>,greater<P> > q;
    vector<long long> ans(n,0);
    rip(i,da[0].size(),0){
        q.push(da[0][i]);
    }
    while (!q.empty()){
        P x=q.top();
        q.pop();
        if(ans[x.second]==0 && x.second!=0){
            ans[x.second]=x.first;
            rip(i,da[x.second].size(),0){
                q.push(make_pair(x.first+da[x.second][i].first,da[x.second][i].second));
            }
        }
    }
    rip(i,n,0){
        cout << i << ' ' << ans[i] << endl;
    }
}

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

#define MAX 100
#define INF INT_MAX
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
int col[MAX];
int M[MAX][MAX];
int d[MAX];
int p[MAX];

void init(int n) {
	for (int i = 0; i < n; i++) {
		col[i] = WHITE;
		for (int j = 0; j < n; j++)
			M[i][j] = INF;
		d[i] = INF;
	}
}

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

void dijkstra(int s) {
	d[s] = 0;
	p[s] = -1;
	while (true) {
		int minc = INF;
		int u;
		for (int i = 0; i < n; i++) {
			if (col[i] != BLACK && d[i] < minc) {
				minc = d[i];
				u = i;
			}
		}
		if (minc == INF) break;
		col[u] = BLACK;
		for (int v = 0; v < n; v++) {
			if (col[v] != BLACK && M[u][v] != INF) {
				if (d[u] + M[u][v] < d[v]) {
					d[v] = d[u] + M[u][v];
					p[v] = u;
					col[v] = GRAY;
				}
			}
		}
	}
}

void output() {
	for (int u = 0; u < n; u++)
		cout << u << " " << d[u] << endl;
}

int main() {
	cin >> n;
	init(n);
	input();
	dijkstra(0);
	output();
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define INF 1000000000

int n;
int g[100][100];
int d[100],p[100];

void dijkstra(int start){
  d[start]=0;
  int mn,t,cnt=0;
  while(cnt<=n){
    mn=INF;
    for(int i=0;i<n;i++){
      if(p[i]==0 && mn>d[i]){
	mn=d[i];
	t=i;
      }
    }
    for(int i=0;i<n;i++){
      d[i]=min(g[t][i]+d[t],d[i]);
    }
    p[t]=1;
    cnt++;
  }
}


    
int main(){
  int u,k,v,c;
  for(int i=0;i<100;i++){
    p[i]=0;
    d[i]=INF;
    for(int j=0;j<100;j++){
      if(i==j) g[i][j]=0;
      else g[i][j]=INF;
    }
  }
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      g[u][v]=c;
    }
  }
  dijkstra(0);
  for(int i=0;i<n;i++){
    cout<<i<<" "<<d[i]<<endl;
  }
  return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cassert>
#include<cctype>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<functional>
#include<limits>
#include<list>
#include<map>
#include<numeric>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL

//????????¨???????????????????????°??????????????\?????????????????????

#define MAX 100

using Weight = int;
struct Edge {
	int s; //source
	int d; //destination
	Weight w; //weight
	Edge(int s = 0, int d = 0, int w = INF) : s(s), d(d), w(w) {};
};
using Edges = vector<Edge>;
//???????????\???
//g[u].push_back(Edge(u, v, c));
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

//?????¢?´¢, ??¢?´¢???, ??¢?´¢???
enum { WHITE, GRAY, BLACK };

//???????§????????????? (Dijkstra)
//dist: ?§????????????????????????§??????????????¢
//prev: ???????????¨????????????
void dijkstra(Graph g, int s, vector<Weight> &dist, vector<int> &prev) {
	typedef tuple<Weight, int, int> State; //?§?????????????????°?????????? ??? ???
	priority_queue<State, vector<State>, greater<State> >PQ;
	vector<int> color(g.size(), WHITE);
	dist.assign(g.size(), INF); //distance
	prev.assign(g.size(), -1);
	dist[s] = 0; PQ.push(State(0, s, -1)); color[s] = GRAY; //?§????
	while (!PQ.empty()) {
		Weight d; int v; int u;
		tie(d, v, u) = PQ.top(); PQ.pop(); //dist???????°??????¨??????????´????????????????
		if (dist[v] < d) continue; //?????§???????????§???????????°??????
		color[v] = BLACK;
		prev[v] = u;
		for (auto e : g[v]) { //??£??\????????????????????¨????????????		
			if (color[e.d] == BLACK)continue; //??¢?´¢????????????
			if (dist[e.d] > dist[v] + e.w) {
				dist[e.d] = dist[v] + e.w;
				PQ.push(State(dist[e.d], e.d, v));
				color[e.d] = GRAY;
			}
		}
	}
}

//?§?????????????????????§??????????????????
//???????????????????????°?????????????§??????????????????§?????????????????¢????????????
vector<int> getPath(int s, int g, vector<int> prev) {
	vector<int> path;
	for (int i = g; i != s; ) path.push_back(i = prev[i]);
	reverse(path.begin(), path.end());
	return path;
}

//???????????????
void printPath(vector<int> path) {
	cout << "Path: ";
	for (auto p : path) cout << p << " ";
	cout << endl;
}

int main() {
	int n; cin >> n;
	Graph g(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);
			g[u].push_back(Edge(u, v, c));
		}
	}
	vector<Weight> dist;
	vector<int> prev;
	dijkstra(g, 0, dist, prev);
	for (int i = 0; i < n; i++) {
		printf("%d %d\n", i, dist[i]);
		//printPath(getPath(0, i, prev));
	}
	return 0;
}