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 <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <queue>
#include <utility>
using namespace std;
//_____
#define pb push_back
#define fi first
#define se second
#define mkp make_pair
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0; i<(n); ++i)
#define reps(i,f,n) for(int i=(f); i<=(n); ++i)
#define err(...) fprintf(stderr, __VA_ARGS__)
#define show(x) cerr << #x << ':' << x << endl
#define outl(x) cout << (x) << '\n'
#define FAST() cin.tie(0), ios::sync_with_stdio(false)
typedef long long ll;
typedef pair<int,int> pii;
template<class A, class B>inline bool chmax(A &a, B b){return b>a ? a=b,1 : 0;}
template<class A, class B>inline bool chmin(A &a, B b){return b<a ? a=b,1 : 0;}
inline bool inside(int y, int x, int H, int W){return(y>=0 && x>=0 && y<H && x<W);}
const int dx[] = {1, 0, -1, 0,  1, 1, -1, -1};
const int dy[] = {0, 1, 0, -1,  -1, 1, 1, -1};
#define INF 0x3f3f3f3f
#define LEN 1000011
#define NIL -1
//_______

int N;
vector <pii> G[101];
int mcos[101];

void dijkstra(int s)
{
   priority_queue < pii, vector<pii>, greater<pii> > pq;
   pq.push( mkp(0, s) );
   memset( mcos, INF, sizeof(mcos) );
   mcos[s] = 0;

   while( !pq.empty() ){
      const pii tmp = pq.top(); pq.pop();
      if( mcos[tmp.se] < tmp.fi )continue;

      for( const auto& v : G[tmp.se] ){
         const int nc = v.fi + tmp.fi;
         if( chmin( mcos[v.se], nc )) pq.push( mkp(nc, v.se) );
      }
   }
   return ;
}

signed main()
{
   FAST();
   cin >> N;
   rep(i, N){
      int u, k, to, c;
      cin >> u >> k;
      while(k--){
         cin >> to >> c;
         G[i].pb( mkp(c,to) );
      }
   }
   dijkstra(0);
   rep(i, N){
      cout << i << ' ' << mcos[i] << '\n';
   }
}

C++: #include<iostream>
#include<string>
using namespace std;

void dijkstra(int s);
const int Infty = 20000000;

int **M,*d,*p,n;
string *color;

int main(){
	cin>>n;
	M = new int*[n]; for(int i=0;i<n;i++) M[i] = new int[n];
	d = new int[n]; p = new int[n]; color = new string[n];
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++) M[i][j] = -1;
	}

	for(int i=0;i<n;i++){
		int vertex,deg,e,w;
		cin>>vertex>>deg;
		for(int j=0;j<deg;j++){
			cin>>e>>w;
			M[i][e]  = w;
		}
	}

	dijkstra(0);

	for(int i=0;i<n;i++) delete [] M[i]; delete [] M;
	delete [] d; delete [] p; delete [] color;
}

void dijkstra(int s){
	for(int i=0;i<n;i++){
		d[i] = Infty; color[i] = "WHITE";
	}
	d[s] = 0; p[s] = -1;

	while(true){
		int u , mindist = Infty;
		for(int i=0;i<n;i++){
			if(color[i]!="BLACK" && d[i]<mindist){
				mindist = d[i];
				u = i;
			}
		}

		if(mindist==Infty) break;

		color[u] = "BLACK";

		for(int v=0;v<n;v++){
			if(color[v]!="BLACK" && M[u][v]!=-1){
				if(d[u]+M[u][v]<d[v]){
					d[v] = d[u]+M[u][v];
					p[v] = u;
					color[v] = "GRAY";
				}
			}
		}
	}

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

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n) ; i++)
constexpr auto INF = 2147483647;
typedef long long ll;

static const int MAX = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, Adj_Marix[MAX][MAX];

void dijkstra(){
  int minv;
  int distance[MAX], color[MAX];
  //init
  for(int i=0;i<n; i++){
    distance[i] = INF;
    color[i] = WHITE;
  }
  distance[0] = 0;
  color[0] = GRAY;
  while(1){
    minv = INF;
    int u  = -1;
    // Find next point
    for(int i =0; i<n; i++){
      if( minv > distance[i] && color[i] != BLACK){
        u = i;
        minv = distance[i];
      }
    }
    //if cant find next point
    if(u == -1) break;
    // Refresh dictance for adj points
    color[u] = BLACK;
    for(int v=0; v<n; v++){
      if(color[v] != BLACK && Adj_Marix[u][v] != INF){
        if(distance[v] > distance[u] + Adj_Marix[u][v]){
          distance[v] = distance[u] + Adj_Marix[u][v];
          color[v] = GRAY;
        }
      }
    }
  }
  for(int i =0; i<n; i++){
    cout << i << " " << (distance[i] == INF ? -1: distance[i] ) << endl;
  }
}

int main(){

  cin >> n;
  rep(i,n){
    rep(j,n){
      Adj_Marix[i][j] = INF;
    }
  }

  int k, c, u, v;
  rep(i,n){
    cin >> u >> k;
    rep(j,k){
      cin >> v >> c;
      Adj_Marix[u][v] = c;
    }
  }

  dijkstra();

  return 0;
}

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

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef stack<int> SI;
typedef queue<int> QI;
typedef pair<int,int> PII;
typedef long long LL;

#define d(x)  cout<<#x<<" = "<<(x)<<endl;
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define REACH(i,c) for(typeof((c).rbegin()) i=(c).rbegin(); i!=(c).rend(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c,n) sort(c,c+n)
#define VSORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define DFOR(i,b,a) for(int i=(b)-1;i>=(a);--i)
#define DREP(i,n) DFOR(i,n,0)
#define INF 1000000000

const double EPS = 1e-10;
const double PI  = acos(-1.0);
////////////////////////////////////////////////
int a[100][100],n,judge,s[100],d[101],p[100];

int main()
{
	cin>>n;
	REP(i,n)
	{
		REP(j,n)a[i][j]=INF;
	}
	REP(i,n)
	{
		int node,m;cin>>node>>m;
		REP(j,m)
		{
			int x,cost;cin>>x>>cost;
			a[node][x]=cost;
		}
	}
	
	REP(i,n+1)d[i]=INF;
	d[0]=0;
	for(;;)
	{
		int u=n;
		REP(i,n)
		{
			if(s[i]==0&&d[u]>d[i])u=i;
		}
		s[u]=1;
		if(d[u]==INF)break;
		REP(i,n)
		{
			if(d[u]+a[u][i]<d[i]&&s[i]==0)
			{
				d[i]=d[u]+a[u][i];
				p[i]=u;
			}
		}
	}
	REP(i,n)cout<<i<<" "<<d[i]<<endl;
	return 0;
}