Go: // ダイクストラのアルゴリズム
package main

import (
	"bufio"
	"fmt"
	"log"
	"math"
	"os"
	"strconv"
	"strings"
)

type color int

const (
	white color = iota // 未訪問
	mst                // MSTとして確定
)

// 頂点
type node struct {
	num       int         // 頂点の番号
	weights   map[int]int // 重みMAP
	parent    *node       // MSTへの重み最小の親
	distFromS int         // 始点からの距離
	color     color
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	n := eGetInt(scanner)

	nodes := make([]*node, n)
	for i := 0; i < n; i++ {
		weights := eAtoi((strings.Fields(eGetline(scanner))))
		v := &node{weights[0], make(map[int]int, weights[1]), nil, math.MaxInt32, white}
		for j := 0; j < weights[1]; j++ {
			k := weights[j*2+2] // 相手の頂点名
			w := weights[j*2+3] // 重み
			v.weights[k] = w
		}
		nodes[i] = v
	}

	// 初回はnode[0]がMSTに入るように
	nodes[0].distFromS = 0

	for { // 全部チェックするまで

		// どの頂点を新たにMSTに取り込むか

		var minNode *node
		min := math.MaxInt32
		for _, v := range nodes {
			if v.color == mst {
				continue
			}
			if v.distFromS < min {
				min = v.distFromS
				minNode = v
			}
		}
		if minNode == nil {
			// すべて完了している.
			break
		}

		// MSTに追加する頂点決定
		minNode.color = mst

		// fmt.Printf(">[%v]\n", minNode)
		// MSTに属していない頂点それぞれについて,Startからの最小の重みの距離を更新
		for i, v := range nodes {
			if v.color == mst {
				continue
			}
			w, ok := minNode.weights[i]
			if !ok {
				// minNodeと接してない
				continue
			}

			if minNode.distFromS+w < v.distFromS {
				// minNode経由の距離がもっとも重みが少ないので親を変更
				v.distFromS = minNode.distFromS + w
				v.parent = minNode
				// fmt.Printf("[%v %v]\n", v, minNode)
			}
		}
		// fmt.Printf("<\n")
	}

	for i, v := range nodes {
		fmt.Printf("%d %d\n", i, v.distFromS)
	}
}

func eGetInt(scanner *bufio.Scanner) int {
	t := eAtoi(strings.Fields(eGetline(scanner)))
	return t[0]
}

func eGetline(p *bufio.Scanner) string {
	if !p.Scan() {
		if err := p.Err(); err != nil {
			log.Fatal(err.Error())
		}
		return ""
	}
	return p.Text()
}

func eAtoi(s []string) []int {
	ints := make([]int, len(s))
	var err error
	for i, e := range s {
		ints[i], err = strconv.Atoi(e)
		if err != nil {
			log.Fatal(err.Error())
		}
	}
	return ints
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int inf = 1<<29;
int n;
vector<pair<int, int>> G[110];
vector<int> d(110, inf);

void dijkstra(int s){
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> qu;
    d[s] = 0;
    qu.push(make_pair(0, s));

    while(!qu.empty()){
        pair<int, int> p = qu.top(); qu.pop();
        if(d[p.second] < p.first) continue;
        for(auto e:G[p.second]){
            if(d[e.second] > p.first+e.first){
                d[e.second] = p.first+e.first;
                qu.push(make_pair(d[e.second], e.second));
            }
        }
    }
}

int main(){
    cin >> n;
    for(int i=0; i<n; ++i){
        int u, k; cin >> u >> k;
        for(int j=0; j<k; ++j){
            int v, w; cin >> v >> w;
            G[u].push_back(make_pair(w, v));
        }
    }

    dijkstra(0);
    for(int i=0; i<n; ++i){
        cout << i << ' ' << d[i] << '\n';
    }

    return 0;

}

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

using WNode = std::pair<uint32_t, uint32_t>;
using WGraph = std::vector<std::vector<WNode>>;

int main() {
  uint32_t N = 0;
  std::cin >> N;
  WGraph G(N);
  for (size_t i = 0; i < N; i++) {
    uint32_t K = 0;
    std::cin >> i >> K;
    for (size_t j = 0; j < K; j++) {
      uint32_t node = 0, cost = 0;
      std::cin >> node >> cost;
      G[i].push_back({node, cost});
    }
  }

  const uint32_t start = 0;
  std::vector<uint32_t> min_cost(N, -1);
  min_cost[start] = 0;
  std::vector<uint32_t> prev_node(N, -1);
  prev_node[start] = start;
  std::vector<bool> visit(N, false);
  for (size_t i = 0; i < N; i++) {
    uint32_t current = 0, min = -1;
    for (size_t j = 0; j < N; j++) {
      if (visit[j] || min_cost[j] >= min) continue;
      min = min_cost[j];
      current = j;
    }
    visit[current] = true;

    for (auto &&g : G[current]) {
      if (min_cost[g.first] <= g.second + min_cost[current]) continue;
      min_cost[g.first] = g.second + min_cost[current];
      prev_node[g.first] = current;
    }
  }

  for (size_t i = 0; i < N; i++) {
    std::cout << i << " " << min_cost[i] << std::endl;
  }

  return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX =100;
static const int INFTY = (1<<21);
static const int WHITE =0;
static const int GRAY = 1;
static const int BLACK = 2;
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 k,c,u,v;
  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;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#define MAX_V 100
#define INF 1e9
using namespace std;
int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;
void dijkstra(int s) {
	for (int i = 0; i < V; i++) {
		d[i] = INF;
		used[i] = false;
	}
	d[s] = 0;
	while (true) {
		int v = -1;
		for (int u = 0; u < V; u++) {
			if (!used[u] && ((v == -1) || d[u] < d[v])) {
				v = u;
			}
		}
		//全ての頂点が到達済み
		if (v == -1) {
			break;
		}
		//集合に新たに頂点を追加
		used[v] = true;
		for (int u = 0; u < V; u++) {
			if (cost[v][u] != -1) {
				d[u] = min(d[u], d[v] + cost[v][u]);
			}
		}
	}
}

int main() {
	for (int i = 0; i < MAX_V; i++) {
		for (int j = 0; j < MAX_V; j++) {
			cost[i][j] = -1;
		}
	}
	cin >> V;
	for (int i = 0; i < V; i++) {
		int u;
		cin >> u;
		int k;
		cin >> k;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			int c;
			cin >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);

	for (int i = 0; i < V; i++) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

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

using std::cin;
using std::cout;
using std::cerr;
using std::endl;

/*
 * dijkstra 法 O(Elog(V))
 * グラフ g において, 始点 start から各頂点への最短経路を返す
*/
struct Edge {
public:
  int to, cost;

  Edge() {}
  Edge(int to, int cost) : to(to), cost(cost) {}
};

std::vector<int> dijkstra(std::vector<std::vector<Edge> >& graph, int start) {
  std::vector<int> d(graph.size(), int(1e9));
  // (x, y) ... x : the minimum distance from start to y, y : now vertex 
  std::priority_queue<std::pair<int, int> > que;

  que.push({0, start});
  d[start] = 0;

  while(!que.empty()) {
    auto p = que.top();
    que.pop();

    for (auto e : graph[p.second]) {
      if (d[e.to] <= p.first + e.cost) continue;

      d[e.to] = p.first + e.cost;
      que.push({d[e.to], e.to});
    }
  }

  return d;
}


int main() {
  int n, u, k, v, c;
  std::vector<std::vector<Edge> > g;

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

  auto d = dijkstra(g, 0);

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

  return 0;
}