Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF (1 << 21)
typedef long long ll;

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

  vector<int> V[n];
  int E[n][n];
  int d[n];
  int visited[n];

  REP(x, n) {
    REP(y, n) {
      E[x][y] = INF;
    }
    d[x] = INF;
    visited[x] = 0;
  }

  REP(_, n) {
    int u, k;
    cin >> u >> k;
    REP(__, k) {
      int v, c;
      cin >> v >> c;
      V[u].push_back(v);
      E[u][v] = c;
      E[v][u] = c;
    }
  }

  d[0] = 0;
  REP(_, n) {
    int minv = -1;
    int mincost = INF;
    REP(v, n) {
      if (!visited[v] && d[v] < mincost) {
        minv = v;
        mincost = d[v];
      }
    }
    visited[minv] = 1;
    for (auto it = V[minv].begin(); it != V[minv].end(); it++) {
      if (E[minv][*it] < INF && d[minv] + E[minv][*it] < d[*it]) {
        d[*it] = d[minv] + E[minv][*it];
      }
    }
  }

  REP(i, n) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, start, n) for (int i = (int)(start); i < (int)(n); ++i)
static const int INFTY = (1 << 30);
int n;
void search(vector<vector<int> > &G1, vector<vector<int> > &G2, int *d, bool *v)
{
    int mini, minv;
    while (1)
    {
        bool iscomp = true;
        minv = INFTY;
        rep(i, 0, n)
        {
            if (!v[i] && d[i] < minv)
            {
                mini = i;
                minv = d[i];
                iscomp = false;
            }
        }
        if (iscomp)
            break;
        v[mini] = true;
        rep(i, 0, G1[mini].size())
        {
            int tmp = G1[mini][i];
            if (!v[tmp])
            {
                int tmptime = minv + G2[mini][i];
                if (tmptime < d[tmp])
                    d[tmp] = tmptime;
            }
        }
    }
}
int main()
{
    cin >> n;
    vector<vector<int> > G1(n, vector<int>(0)), G2(n, vector<int>(0));
    int d[n];
    bool v[n] = {};
    rep(i, 0, n) d[i] = INFTY;
    int utmp, ktmp, vtmp, ctmp;
    rep(i, 0, n)
    {
        cin >> utmp >> ktmp;
        rep(j, 0, ktmp)
        {
            cin >> vtmp >> ctmp;
            G1[utmp].push_back(vtmp);
            G2[utmp].push_back(ctmp);
        }
    }
    d[0] = 0;
    search(G1, G2, d, v);
    rep(i, 0, n)
    {
        printf("%d %d\n", i, d[i]);
    }
}

C++: #include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	int n;
	cin >> n;

	vector<vector<pair<int, int>>> m(n);

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

	vector<int> d(n, INF), color(n);

	d[0] = 0;
	color[0] = 1;
	while (true) {
		int minv = INF;
		int u = -1;
		for (int i = 0; i < n; i++) {
			if (minv > d[i] && color[i] != 2) {
				u = i;
				minv = d[i];
			}
		}

		if (u == -1) {
			break;
		}

		color[u] = 2;
		for (auto e : m[u]) {
			if (color[e.first] != 2 && d[e.first] > d[u] + e.second) {
				d[e.first] = d[u] + e.second;
				color[e.first] = 1;
			}
		}
	}

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

C++: #include <stdio.h>
#define INF 10000000
typedef struct{
	int node;
	int cost;
} List;

int dist[101];
List list[101][101];
int kazu[101];

int n;

void walk(int x,int step){
	dist[x]=step;
	for(int i=0;i<kazu[x];i++){
		if(dist[list[x][i].node]>step+list[x][i].cost) walk(list[x][i].node,step+list[x][i].cost);
	}
}

int main(void){
	int i,j,w;
	int num;
	scanf("%d",&n);
	for(i=0;i<n;i++){
		scanf("%d",&num);
		scanf("%d",kazu+num);
		for(j=0;j<kazu[num];j++)scanf("%d %d",&(list[num][j].node),&list[num][j].cost);
	}
	for(i=0;i<n;i++) dist[i]=INF;
	walk(0,0);
	
	for(i=0;i<n;i++){
		printf("%d %d\n",i,dist[i]);
	}
	return 0;
}