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>
#define INF 1e9
using namespace std;

int main(){
    //declaration and input
    int n;
    cin >> n;
    int u, k;
    vector<vector<int>> graph(n, vector<int>(n, INF));
    for (int i = 0; i < n; i++){
        cin >> u >> k;
        int v, c;
        for (int j = 0; j < k; j++){
            cin >> v >> c;
            graph[u][v] = c;
        }
    }
    vector<int> cost(n, INF);
    vector<int> parent_of(n, -1);
    vector<bool> is_visit(n, false);

    //Dijkstra
    //init
    cost[0] = 0;
    
    //loop
    while(true){
        int mincost = INF;
        int next = -1;
        for (int i = 0; i < n; i++){
            if (!is_visit[i] && cost[i] < mincost){
                mincost = cost[i];
                next = i;
            }
        }
        if (next == -1)
            break;
        is_visit[next] = true;
        for (int i = 0; i < n; i++){
            if (!is_visit[i] && graph[next][i] < INF){
                if (cost[next] + graph[next][i] < cost[i]){
                    cost[i] = cost[next] + graph[next][i];
                    parent_of[i] = next;
                }
            }
        }
    }

    //output
    for (int i = 0; i < n; i++)
        cout << i << ' ' << cost[i] << endl;
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define INF 1<<20

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int cost[105][105];
int d[105];
bool used[105];

int dijkstra (int n )
{
	memset (used, false, sizeof (used ) );
	fill (d, d+n, INF );
	d[0] = 0;

	while (true ){
		int v = -1;
		// まだ使われていない頂点のうち距離が最小のものを探す
		rep (u, n )
			if (!used[u] && (v == -1 || d[u] < d[v] ) ) v = u;
		
		if (v == -1 ) break;
		
		used[v] = true;
		rep (u, n )
			d[u] = min (d[u], d[v] + cost[v][u] );
	} // end whle
}

int main()
{
	ios_base::sync_with_stdio(0);
	int n; cin >> n;
	rep (i, n ) rep (j, n ) cost[i][j] = INF;

	rep (i, n ){
		int u; cin >> u;
		int k; cin >> k;
		while (k-- ){
			int v, c; cin >> v >> c;
			cost[u][v] = c;
		} // end while
	} // end loop

	dijkstra (n );
	rep (i, n ) cout << i << ' ' << d[i] << endl;
		
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <queue>


void update(int node, std::vector<int>& weight, const std::vector<std::map<int, int>> link_list) {
    for (auto && l : link_list[node]) {
        if (weight[l.first] == -1 || weight[node] + l.second < weight[l.first]) {
            weight[l.first] = weight[node] + l.second;
            update(l.first, weight, link_list);
        }
    }
}


int main() {
    int n;
    std::cin >> n;

    std::vector<std::map<int, int>> link_list;
    for (int i = 0; i < n; i++) {
        int u, k;
        std::cin >> u >> k;
        std::map<int, int> map;
        for (int j = 0; j < k; j++) {
            int c, v;
            std::cin >> c >> v;
            map[c] = v;
        }
        link_list.emplace_back(map);
    }

    std::vector<int> weight(n, -1);
    weight[0] = 0;

    auto comp = [] (std::tuple<int, int, int> &lfs, std::tuple<int, int, int> &rhs) {
        return std::get<2>(lfs) > std::get<2>(rhs);
    };
    
    std::priority_queue<std::tuple<int, int, int>, std::vector<std::tuple<int, int, int>>, decltype(comp)> que(comp);
    for (auto && m : link_list[0]) {
        que.push(std::make_tuple(0, m.first, m.second));
    }

    while (!que.empty()) {
        auto val = que.top();
        que.pop();
        auto w = weight[std::get<0>(val)] + std::get<2>(val);
        if (weight[std::get<1>(val)] == -1 || w < weight[std::get<1>(val)]) {
            weight[std::get<1>(val)] = w;
            for (auto && m : link_list[std::get<1>(val)]) {
                que.push(std::make_tuple(std::get<1>(val), m.first, m.second));
            }
        }
    }

    for (int i = 0; i < n; i++) {
        std::cout << i << " " << weight[i] << std::endl;
    }
}