Go: package main

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

//make priority queue
type Item struct {
	id       int
	priority int // this state is priority and distans from start
	index    int
}

type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }

// we want the ascending-priority-queue.
// So we use less than here.
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = j
	pq[j].index = i
}

func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}

func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 //for safety
	*pq = old[0 : n-1]
	return item
}

func (pq *PriorityQueue) update(dist int, id int) {
	for _, i := range *pq {
		if i.id == id {
			if i.priority > dist {
				i.priority = dist
			}
		}
	}
}

// the main code
func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())
	return n
}

func dikstra(dist [][]int, n int) []int {
	// preparate priority queue
	inf := 1 << 30
	pq := make(PriorityQueue, n)
	shortests := make([]int, n)
	for i := 0; i < n; i++ {
		pq[i] = &Item{
			id:       i,
			priority: inf,
			index:    i,
		}

		shortests[i] = inf
	}
	pq[0].priority = 0
	shortests[0] = 0
	heap.Init(&pq)

	for pq.Len() > 0 {
		item := heap.Pop(&pq).(*Item)
		shortests[item.id] = item.priority
		for id, d := range dist[item.id] {
			if d != -1 {
				pq.update(item.priority+d, id)
			}
		}
		heap.Init(&pq)
	}
	return shortests
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	// init
	n := nextInt(sc)
	dist := make([][]int, n)
	for i := 0; i < n; i++ {
		dist[i] = make([]int, n)
		for j := 0; j < n; j++ {
			dist[i][j] = -1
		}
	}

	// std Input
	for i := 0; i < n; i++ {
		u := nextInt(sc)
		k := nextInt(sc)
		for j := 0; j < k; j++ {
			v, c := nextInt(sc), nextInt(sc)
			dist[u][v] = c
		}
	}

	shortests := dikstra(dist, n)
	for i, d := range shortests {
		fmt.Printf("%d %d\n", i, d)
	}
}

C++: // #include {{{
#include <array>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <string>
#include <algorithm>
#include <numeric>
#include <functional>
#include <iterator>
#include <tuple>
#include <utility>
#include <random>
#include <limits>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cstdint>
#include <cassert>
// }}}

using namespace std;

// macros {{{
template<typename T, size_t N>
constexpr size_t NELEMS(T (&)[N]) { return N; }

template<typename InputIt>
void PRINT_RANGE(InputIt first, InputIt last)
{
    for(; first != last; ++first)
        cout << *first << (first==last ? "" : " ");
    cout << "\n";
}

template<typename T>
void PRINT_MATRIX(T mat, size_t nr, size_t nc)
{
    for(size_t r = 0; r < nr; ++r) {
        for(size_t c = 0; c < nc; ++c) {
            cout << mat[r][c] << (c==nc-1 ? "" : " ");
        }
        cout << "\n";
    }
}

#define FOR(i, start, end) for(int i = (start); i < (end); ++i)
#define REP(i, n) FOR(i, 0, n)
// }}}

// types {{{
using ll  = long long;
using ull = unsigned long long;
// }}}

constexpr int INF = numeric_limits<int>::max();

int N;
int G[100][100];

void solve()
{
    vector<int> cost(N);
    deque<bool> done(N);

    fill(begin(cost), end(cost), INF);
    cost[0] = 0;

    for(;;) {
        int mincost = INF;
        int minv    = -1;

        REP(v, N) {
            if(done[v]) continue;
            if(cost[v] < mincost) {
                mincost = cost[v];
                minv    = v;
            }
        }

        if(minv == -1) break;

        done[minv] = true;

        REP(v, N) {
            if(done[v]) continue;
            if(G[minv][v] == -1) continue;
            int cost_new = cost[minv] + G[minv][v];
            if(cost_new < cost[v]) {
                cost[v] = cost_new;
            }
        }
    }

    REP(v, N) {
        cout << v << " " << cost[v] << "\n";
    }
}

int main()
{
    cin >> N;
    REP(from, N) {
        REP(to, N) {
            G[from][to] = -1;
        }
    }

    REP(_, N) {
        int from, k;
        cin >> from >> k;
        REP(_, k) {
            int cost, to;
            cin >> to >> cost;
            G[from][to] = cost;
        }
    }

    solve();

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
 
using Weight=int;
struct Edge {
    int src,dest; Weight weight;
    bool operator<(const Edge &rhs)const{
        return weight<rhs.weight;
    }
};
using Edges=vector<Edge>;
using Graph=vector<Edges>;
 
const Weight INF=1e9;
 
void Dijkstra(const Graph &g,int s,vector<Weight> &d){
    assert(0<=s && s<g.size());
    d.assign(g.size(),INF); d[s]=0;
    vector<int> used(g.size(),0);
    using P=pair<Weight,int>;
    priority_queue<P,vector<P>,greater<P>> que;
    que.push({0,s});
    while(!que.empty()){  
        auto val=que.top(); que.pop();
        Weight dist=val.first;
        int v=val.second;
        if(used[v]) continue;
        used[v]=true;
        for(auto e:g[v]){
            int to=e.dest;
            Weight w=e.weight;
            if(dist+w<d[to]){
                d[to]=dist+w;
                que.push({d[to],to});
            }
        }
    }
}

vector<Weight> Dijkstra(const Graph& g,int s){
    vector<Weight> res;
    Dijkstra(g,s,res);
    return res;
}

vector<Weight> DijkstraPath(const Graph &g,int s,vector<int> &prev){
    prev.assign(g.size(),-1);
    prev[s]=s;
    vector<Weight> d(g.size(),INF);
    assert(0<=s && s<g.size());
    d[s]=0;
    vector<int> used(g.size(),0);
    using P=pair<Weight,int>;
    priority_queue<P,vector<P>,greater<P>> que;
    que.push({0,s});
    while(!que.empty()){  
        auto val=que.top(); que.pop();
        Weight dist=val.first;
        int v=val.second;
        if(used[v]) continue;
        used[v]=true;
        for(auto e:g[v]){
            int to=e.dest;
            Weight w=e.weight;
            if(dist+w<d[to]){
                prev[to]=v;
                d[to]=dist+w;
                que.push({d[to],to});
            }
        }
    }
    return d;
}

vector<int> BuildPath(int s,int t,vector<int> &prev){
    vector<int> res;
    if(prev[s]==-1) return res;
    int v=t;
    while(v!=s){
        res.push_back(v);
        v=prev[v];
    }
    res.push_back(s);
    reverse(res.begin(),res.end());
    return res;
}

int main()
{
    int n;
    cin>>n;
    Graph g(n);
    for(int i=0;i<n;i++)
    {
        int k;
        cin>>k>>k;
        for(int j=0;j<k;j++)
        {
            int v;
            cin>>v;  
            Weight c;
            cin>>c;          
            g[i].push_back((Edge){i,v,c});
        }
    }
    vector<Weight> d;
    vector<int> prev;
    d=DijkstraPath(g,0,prev);
    for(int i=0;i<n;i++)
    {
        cout<<i<<" "<<d[i]<<endl;
        /*
        vector<int> path=BuildPath(0,i,prev);
        for(int i=0;i<path.size();i++) cout<<path[i]<<" ";
        cout<<endl;
        */
    }
    return 0;
}