Go: package main

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

const (
	MAX_N      = 100
	MAX_WEIGHT = 100000
)

type Edge struct {
	start  int
	end    int
	weight int
}

type ShortestInfo struct {
	edges    []Edge
	shortest int
}

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

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	shortestList := make([]ShortestInfo, n)
	for i := 1; i < n; i++ {
		shortestList[i] = ShortestInfo{edges: []Edge{}, shortest: MAX_N*MAX_WEIGHT + 1}
	}

	adjacentMatrix, err := createAdjacentMatrix(n, sc)
	if err != nil {
		panic(err)
	}

	sssp([]int{1}, shortestList, adjacentMatrix)
	for _, v := range shortestList {
		fmt.Printf("%d %d\n", v.getEnd()-1, v.shortest)
	}
}

func (si ShortestInfo) getEnd() int {
	if len(si.edges) == 0 {
		return 1
	} else {
		return si.edges[len(si.edges)-1].end
	}
}

func createAdjacentMatrix(n int, sc *bufio.Scanner) ([][]int, error) {
	adjacentMatrix := make([][]int, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		adjacentMatrix[id] = make([]int, n)
		for j := 0; j < n; j++ {
			adjacentMatrix[id][j] = -1
		}
		vertexNum, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		for j := 0; j < vertexNum; j++ {
			v, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			c, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			adjacentMatrix[id][v] = c
		}
	}
	return adjacentMatrix, nil
}

func sssp(nodeStack []int, shortestList []ShortestInfo, adjacentMatrix [][]int) {
	for len(nodeStack) > 0 {
		currentNode := nodeStack[0]
		nodeStack = nodeStack[1:]
		currentShortest := getShortest(currentNode, shortestList)
		adjacents := findAdjacents(currentNode, adjacentMatrix)
		for i := 0; i < len(adjacents); i++ {
			adj := adjacents[i]
			if currentShortest.shortest+adj.weight < getShortest(adj.end, shortestList).shortest {
				setShortest(adj.end, adj, currentShortest, shortestList)
				nodeStack = append(nodeStack, adj.end)
			}
		}
	}
}

func getShortest(node int, shortestList []ShortestInfo) ShortestInfo {
	return shortestList[node-1]
}

func setShortest(node int, edge Edge, currentShortest ShortestInfo, shortestList []ShortestInfo) {
	newEdges := make([]Edge, len(currentShortest.edges)+1)
	for i := 0; i < len(newEdges)-1; i++ {
		newEdges[i] = currentShortest.edges[i]
	}
	newEdges[len(newEdges)-1] = edge
	shortestInfo := ShortestInfo{edges: newEdges, shortest: currentShortest.shortest + edge.weight}
	shortestList[node-1] = shortestInfo
}

func findAdjacents(currentNode int, adjacentMatrix [][]int) []Edge {
	adjacents := adjacentMatrix[currentNode-1]
	edges := []Edge{}
	for i, v := range adjacents {
		if v > 0 {
			edges = append(edges, Edge{start: currentNode, end: i + 1, weight: v})
		}
	}
	return edges
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
using namespace std;
static const int Max = 100;
static const int Inf = 100000000; // ??????
static const int Nil = -1; // 

enum Status {
	Not_Searched = 0,
	Connected = 1,
	Searched = 2
};

int n;
int M[Max][Max] = {};
Status st[Max] = {}; 
int min_cost[Max] = {}; // min cost of point from start
//int parent[Max] = {}; // ??????index

void dijkstra() {
	for (int i = 0; i < n; i++) {
		min_cost[i] = Inf;
	}

	min_cost[0] = 0;
	st[0] = Connected;
	while (1) {
		int mincost = Inf;
		int min_index = Nil;
		for (int i = 0; i < n; i++) {
			if (st[i] != Searched && mincost > min_cost[i]) {
				mincost = min_cost[i];
				min_index = i;
			}
		}
		if (min_index == Nil) break;
		// index ?????????????????????????????????
		st[min_index] = Searched;
		for (int i = 0; i < n; i++) {
			// min_index ??¨???????????£??????????????????????????????????????????
			if (st[i] != Searched && M[min_index][i] != Inf) {
				if (min_cost[i] > min_cost[min_index] + M[min_index][i]) {
					min_cost[i] = min_cost[min_index] + M[min_index][i];
					st[i] = Connected;
				}
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << i << " " << (min_cost[i] == Inf ? -1 : min_cost[i]) << endl;
	}
	return;
}

int main() {
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = Inf;
		}
	}
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int vi, ci;
			cin >> vi >> ci;
			M[i][vi] = ci;
		}
	}
	dijkstra();
	return 0;
}

C++: #include<iostream>
#include<map>
#include<vector>
#include<algorithm>
#include<cmath>
#include<climits>
#include<ctime>
#include<cstring>
#include<stack>
#include<queue>
#include<sstream>
#include<string>

#define ALL(v) (v).begin(),(v).end()
#define REP(i,p,n) for(int i=p;i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define DUMP(list) cout << "{ "; for(auto nth : list){ cout << nth << " "; } cout << "}" << endl
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i);

using namespace std;

struct node{
	int pos;
	int prev;
	double cost;

	node(int t_pos,int t_prev,double t_cost){
		pos = t_pos; prev = t_prev; cost = t_cost;
	}

	bool operator<(const node& a) const { //キューの中身を逆転
		return cost > a.cost;
	}
};

struct root{
	int to;
	double cost;

	root(int t_to,double t_cost){
		to = t_to; cost = t_cost;
	}

};

vector< vector <root> > roots;
int n,m,s,g;

double dp[101][101];

const double INF = 9e9;

void search(){

	fill_n((double *)dp,sizeof(dp)/sizeof(double),INF); //初期化	
	
	priority_queue<node> pq;

	rep(i,roots[s].size()){
	
		root r = roots[s][i];
		
		pq.push( node(r.to,s,r.cost) );
		dp[r.to][s] = r.cost;
	}

	while(!pq.empty()){

		node tn = pq.top();
		pq.pop();

		if( dp[tn.pos][tn.prev] != tn.cost) continue;

		if( tn.pos == g){
			cout << g << " " <<tn.cost << endl;
			return;
		}	

		rep(i,roots[tn.pos].size()){
			root r = roots[tn.pos][i];
			if(r.to == tn.prev) continue;

			for( int j = -1; j< 2; j++){
		//		if( tn.speed + j > 0 && tn.speed +j <= r.speed){
					double cost = tn.cost + r.cost;///(tn.speed+j);
					if( dp[r.to][tn.pos] > cost){
						dp[r.to][tn.pos] = cost;
						pq.push( node( r.to,tn.pos,cost));
					}
				//}
			}
		}
	}

	cout << "unreachable" << endl;
}


int main(){

		cin >> n;

		roots = vector< vector<root> >(n);

    rep(i,n){
      int num,m;
      cin >> num >> m;
      roots[num].push_back( root(num,0));
      rep(j,m){
        int r,cost;
        cin >> r>> cost;
        roots[num].push_back( root(r,cost));
      }
    }
    s=0;
    rep(i,n){
		  g=i;
      search();
    }
}

C++: // Ref : https://book.mynavi.jp/ec/products/detail/id=35408

#include <iostream>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1 << 21);
static const int WHITE = 0; // unsearched state
static const int GRAY = 1; // ungrouped state
static const int BLACK = 2; // grouped state

int n, M[MAX][MAX];

void dijkstra() {
	int minv;
	int d[MAX], color[MAX];

	for (int i = 0; i < n; i++) {
		d[i] = INFTY;
		color[i] = WHITE;
	}

	d[0] = 0;
	color[0] = GRAY;
	while (1) {
		minv = INFTY;
		int u = -1;
		for (int i = 0; i < n; i++) {
			if (minv > d[i] && color[i] != BLACK) {
				u = i;
				minv = d[i];
			}
		}
		if (u == -1) break;
		color[u] = BLACK;
		for (int v = 0; v < n; v++) {
			if (color[v] != BLACK && M[u][v] != INFTY) {
				if (d[v] > d[u] + M[u][v]) {
					d[v] = d[u] + M[u][v];
					color[v] = GRAY;
				}
			}
		}
	}

	for (int i = 0; i < n; i++) {
		cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
	}
}

int main() {
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = INFTY;
		}
	}

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

	dijkstra();

	return 0;
}