Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <limits>
#include <cmath>
#include <numeric>
#include <string>

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
#define rep(i, a, b) for(int i = (a); i < (b); ++i )
#define rrep(i, a, b) for(int i = (a); i > (b); --i )
#define REP(i, a, b) for(int i = (a); i <= (b); ++i )
#define RREP(i, a, b) for(int i = (a); i >= (b); --i )
#define llrep(i, a, b) for(ll i = (a); i < (b); ++i )
#define llrrep(i, a, b) for(ll i = (a); i > (b); --i )
#define llREP(i, a, b) for(ll i = (a); i <= (b); ++i )
#define llRREP(i, a, b) for(ll i = (a); i >= (b); --i )
#define ullrep(i, a, b) for(ull i = (a); i < (b); ++i )
#define ullrrep(i, a, b) for(ull i = (a); i > (b); --i )
#define ullREP(i, a, b) for(ull i = (a); i <= (b); ++i )
#define ullRREP(i, a, b) for(ull i = (a); i >= (b); --i )

template<typename T=int>
class UnionFind {
public:
    explicit UnionFind(unsigned long long n) : rank_(n, 0), p_(n, 0) {
        for (T i = 0; i < n; i++) {
            MakeSet(i);
        }
    }

    void MakeSet(T x) {
        p_[x] = x;
        rank_[x] = 0;
    }

    bool Same(T x, T y) {
        return FindSet(x) == FindSet(y);
    }

    void Link(T x, T y) {
        if (rank_[x] > rank_[y]) {
            p_[y] = x;
        } else {
            p_[x] = y;
            if (rank_[x] == rank_[y]) {
                rank_[y]++;
            }
        }
    }

    void Unite(T x, T y) {
        Link(FindSet(x), FindSet(y));
    }

    T FindSet(T x) {
        if (x != p_[x]) {
            p_[x] = FindSet(p_[x]);
        }
        return p_[x];
    }

private:
    std::vector<T> rank_, p_;
};

class Dijkstra {
public:
    Dijkstra(unsigned long long num, int max_cost) :
            num_(num),
            max_cost_(max_cost),
            v_(num, std::vector<int>(num, max_cost)),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0) {
    };

    void Compute(int start) {
        d_[start] = 0;
        p_[start] = start;
        while (true) {
            int m = -1;
            int min_d = std::numeric_limits<int>::max();
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (min_d > d_[i])) {
                    min_d = d_[i];
                    m = i;
                }
            }
            if (m < 0) {
                break;
            }
            c_[m] = 1;
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (d_[i] > (d_[m] + v_[m][i])) ) {
                    d_[i] = d_[m] + v_[m][i];
                    p_[i] = m;
                }
            }
        }
    }

public:
    int num_;
    int max_cost_;
    std::vector<std::vector<int>> v_;
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<int> p_;
};


int N, Q;

int G[100][100];
int d[100];
int p[100];
int c[100];

int main() {
    cin >> N;
//    rep(i, 0, N) {
//        rep(j, 0, N) {
//            G[i][j] = 10000010;
//        }
//    }
    Dijkstra dj(N, 10000010);
    rep(i, 0, N) {
        int u, k;
        cin >> u >> k;
        rep(j, 0, k) {
            int t, d;
            cin >> t >> d;
            dj.v_[u][t] = d;
        }
    }
    dj.Compute(0);
    rep(i, 0, N) {
        cout << i << " " << dj.d_[i] << endl;
    }
//    rep(i, 0, N) {
//        d[i] = numeric_limits<int>::max();
//    }
//
//    d[0] = 0;
//    p[0] = 0;
//    while (true) {
//        int m = -1;
//        int min_d = numeric_limits<int>::max();
//        rep(i, 0, N) {
//            if ((c[i] == 0) && (min_d > d[i])) {
//                min_d = d[i];
//                m = i;
//            }
//        }
//        if (m < 0) {
//            break;
//        }
//        c[m] = 1;
//        rep(i, 0, N) {
//            if ((d[m] + G[m][i]) < d[i]) {
//                d[i] = d[m] + G[m][i];
//                p[i] = m;
//            }
//        }
//    }
}

C++: #include <bits/stdc++.h>
#define MAX_E 1000000
#define MAX_V 100000
#define INF 1e9
typedef long long ll;
using namespace std;
/*??????????????????????????? O(V*E)*/

//??????from????????????to???????????????cost??????
struct edge{int from, to, cost;};
edge es[MAX_E]; //???
ll d[MAX_V];   //???????????¢
int V,E;        //V???????????°???E????????°

//s???????????????????????????????????????????????¢????±???????.
void Bellman_Ford(int s){
  for(int i=0; i<V ;i++) d[i]=INF;
  d[s]=0;
  while(true){
    bool update=false;
    for(int i=0; i<E ;i++){
      edge e = es[i];
      if(d[e.from] != INF && d[e.to]> d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	update = true;
      }
    }
    if(!update) break;
  }
}

//true??????????????????????????¨??????
bool find_negative_loop(){
  memset(d,0,sizeof(d));

  for(int i=0; i<V ;i++){
    for(int j=0; j<E ;j++){
      edge e = es[j];
      if(d[e.to] > d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	
	//n??????????????´??°???????????????????????????????????¨?????????
	if(i == V-1) return true;
      }
    }
  }
  return false;
}

int main(){
  cin>>V;
  for(int i=0;i<V;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0,v,c;j<k;j++){
      cin>>v>>c;
      es[E++]=(edge){u,v,c};
      es[E++]=(edge){v,u,c};
  }
  }
  
  for(int i=0;i<V;i++){
    Bellman_Ford(i);
    cout <<i<<" "<<d[0]<<endl;
  }
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxx=1010;
const int infinity=1<<30;
int A[maxx][maxx],d[maxx];
bool flag[maxx];
int n,a,b,c;
	
int main (){
	cin>>n;
	for(int i=0;i<n;i++){
		flag[i]=false;
		d[i]=infinity;
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			A[i][j]=infinity;
		}
	}
	for(int i=0;i<n;i++){
		cin>>a>>b;
		for(int j=0;j<b;j++){
			cin>>c;
			cin>>A[a][c];
		}
	}
	d[0]=0;
	while(1){
		int minv=infinity,minj=-1;
		for(int i=0;i<n;i++){
			if(flag[i]==false && d[i]<minv){
				minv=d[i];
				minj=i;
			}
		}
		if(minv==infinity) break;
		flag[minj]=true;
		for(int i =0;i<n;i++){
			if(A[minj][i]!=infinity && flag[i]==false && d[i]>=d[minj]+A[minj][i]){
					d[i]=d[minj]+A[minj][i];
			}
		}
	}
	for(int i=0;i<n;i++) cout<<i<<" "<<(d[i]==infinity ? -1 : d[i])<<endl;
	
	return 0;

}