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<cstdlib>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
const int MAXN = (int)1e2 + 10;
const int INF = (int) 0x3f3f3f3f;

vector<int> g[MAXN],val[MAXN];
int n;
int d[MAXN],vis[MAXN];

void Dijkstra(int s){
    for(int i=1;i<=n;i++) d[i]=INF;
    d[s]=0;
    vis[s]=1;
    for(int i=0;i<g[0].size();i++){
        int v=g[0][i];
        if(!vis[v]) d[v]=min(d[v],d[0]+val[0][i]);
    }
    int cnt=1;
    while(cnt<=n){
        int id=-1;
        for(int i=1;i<=n;i++)if(!vis[i]){
            if(id==-1||d[id]>d[i]) id=i;
        }
        vis[id]=1;
        cnt++;
        for(int i=0;i<g[id].size();i++){
            int v=g[id][i];
            if(!vis[v]) d[v]=min(d[v],d[id]+val[id][i]);
        }
    }
}

void work(){
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        int u,k; scanf("%d%d",&u,&k);
        while(k--){
            int v,c; scanf("%d%d",&v,&c);
            g[u].push_back(v);
            val[u].push_back(c);
        }
    }
    Dijkstra(0);
    for(int i=0;i<n;i++) printf("%d %d\n",i,d[i]);
}

int main(){
    work();
    return 0;
}

/*
5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3
*/

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, N[MAX][MAX];

int prim(){
  int u,minv;
  int d[MAX],p[MAX],color[MAX];

  for(int i = 0;i<n;i++){
    d[i]=INFTY;
    p[i]=-1;
    color[i]=WHITE;
  }
  d[0]=0;

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

int main(){
  cin >>n;

  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      int e; cin >>e;
      M[i][j] =(e==-1) ? INFTY : e;
    }
  }

  cout << prim() << 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 dik(){
int min;
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){
min=INFTY;
int u=-1;
for(int i=0;i<n;i++){
if(min>d[i]&&color[i]!=BLACK){
u=i;
min=d[i];
}
}
if(u==-1)break;
color[u]=BLACK;
for(int v=0;v<n;v++){
if(color[v]!=BLACK&&M[u][v]){
d[v]=d[u]+M[u][v]){
color[v]=GRAY;
}
}
}
}
for(int i=0;i<n;i++){
cout << i <<" "<<(d[i]==INTY ? -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;
}
}

dik();

return 0;
}

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

using namespace std;

struct adja {
    int v;
    int c;
};

int n;
vector<adja> g[100];
int d[100];

void search() {
    fill_n(d, n, 1 << 20);
    queue<int> q;
    q.push(0);
    d[0] = 0;
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (int i = 0, s = g[u].size(); i < s; ++i) {
            if (d[g[u][i].v] > d[u] + g[u][i].c) {
                d[g[u][i].v] = d[u] + g[u][i].c;
                q.push(g[u][i].v);
            }
        }
    }
}

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