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 <cstdio>
#include <queue>
#include <utility>
using namespace std;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> *adj;
int *d;

void dijkstra() {
    priority_queue<pair<int, int>> PQ;
    int d[n], color[n];

    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
        color[i] = WHITE;
    }
    d[0] = 0;
    PQ.push(make_pair(0, 0));

    while (!PQ.empty()) {
        pair<int, int> f = PQ.top();
        PQ.pop();

        int u = f.second;
        color[u] = BLACK;

        if (d[u] < f.first * (-1)) { continue; }

        for (int j = 0; j < adj[u].size(); j++) {
            int v = adj[u][j].first;
            if (color[v] == BLACK) { continue; }
            if (d[u] + adj[u][j].second < d[v]) {
                d[v] = d[u] + adj[u][j].second;
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;
            }
        }
    }
    
    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, d[i]);
    }
}

int main() {
    scanf("%d", &n);
    adj = new vector<pair<int, int>>[n];
    for (int i = 0; i < n; i++) {
        int u, k;
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; j++) {
            int v, c;
            scanf("%d %d", &v, &c);
            adj[u].push_back(make_pair(v, c));
        }
    }

    dijkstra();

    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#define INF 9999999
using namespace std;

const int maxn = 10000 + 5;
const int maxm = 500000 + 5;

struct Edge{
	int next;
	int to;
	int value;
	Edge():next(0),to(0),value(INF){}
}G[maxm];

struct Node{
	int to;
	int dist;
	bool operator < (const Node& rhs) const{
		return dist > rhs.dist;
	}
};

int head[maxn],cnt;
int dis[maxn];
bool vis[maxn];

int n;

void Insert(int u,int v,int c){
	G[++cnt].next = head[u];
	G[cnt].to = v;
	G[cnt].value = c;
	head[u] = cnt;
}

void init(){
	memset(dis,INF,sizeof(dis));
	memset(vis,false,sizeof(vis));
}

priority_queue<Node >Q;

void Dijkstar(int s){
	dis[s] = 0;
	Q.push((Node){s,0});
	while(!Q.empty()){
		int u = Q.top().to;Q.pop();
		if(vis[u])continue;
		vis[u] = true;
		for(int e = head[u];e; e = G[e].next){
			int v = G[e].to;
			if(dis[u] + G[e].value < dis[v] && !vis[v]){
				dis[v] = dis[u] + G[e].value;
				Q.push((Node){v,dis[v]});
			}
		}
	}
}

int main(){
	init();
	scanf("%d",&n);
	for(int i = 0;i < n; i++){
		int u,m;
		scanf("%d%d",&u,&m);
		for(int j = 0;j < m; j++){
			int v,c;
			scanf("%d%d",&v,&c);
			Insert(u,v,c);
		}
	}
	Dijkstar(0);
	for(int i = 0;i < n; i++){
		printf("%d %d\n",i,dis[i]);
	}
}

C++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_12_B: Single Source Shortest Path I

#include <algorithm>
#include <cstdio>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  const uint INFINIT;
  
public:

  Graph(uint n) : n_(n), g_(new uint[(n_*n_)]), INFINIT(100000*(n_-1)+1) {
    std::fill_n(g_, (n_*n_), INFINIT);
  }

  ~Graph() { delete[] g_; }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  void dijkstra(uint* dist)
  {
    std::fill_n(dist, n_, INFINIT);
    auto i = 0u; // 0-start
    dist[i] = 0u;
    for (auto n = 0u; n < n_-1; ++n) {
      auto cur_min = INFINIT;
      auto cs = (*this)[i];
      auto c = dist[i];
      for (auto j = 0u; j < n_; ++j) {
        auto nc = c+cs[j];
        if (dist[j] < nc) continue;
        dist[j] = nc;
        if (cur_min > nc) {
          i = j;
          cur_min = nc;
        }
      }
    }
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

  uint u, k, v, c;
  for (auto i = 0u; i < n; ++i) {
    std::scanf("%u %u", &u, &k);
    for (auto j = 0u; j < k; ++j) {
      std::scanf("%u %u", &v, &c);
      g[u][v] = c;
    }
  }

  uint dist[n];
  g.dijkstra(dist);
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %u\n", i, dist[i]);
  }
}

// eof

C++: #include <iostream>
using namespace std;
const int MAXn = 100;
const int INFTY = 1 << 21;

int n, M[MAXn][MAXn], col[MAXn], d[MAXn], p[MAXn];

void dijkstra(int s) {
    for(int i = 0; i < n; i++) {
        col[i] = 0;
        d[i] = INFTY;
    }
    d[s] = 0;
    p[s] = -1;

    while(1) {
        int mincost = INFTY;
        int u;
        for(int i = 0; i < n; i++) {
            if(col[i] != 2 && d[i] < mincost) {
                mincost = d[i];
                u = i;
            }
        }
        if(mincost == INFTY) break;
        col[u] = 2;
        for(int v = 0; v < n; v++) {
            if(col[v] != 2 && M[u][v] != INFTY) {
                if(d[u] + M[u][v] < d[v]) {
                    d[v] = d[u] + M[u][v];
                    p[v] = u;
                    col[v] = 1;
                }
            }
        }
    }

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

    return;
}

int main() {
    cin >> n;
    int id, k, v, c;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++) M[i][j] = INFTY;
    for(int i = 0; i < n; i++) {
        cin >> id >> k;
        for(int j = 0; j < k; j++) {
            cin >> v >> c;
            M[id][v] = c;
        }
    }
    dijkstra(0);
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#define MAX 105
#define INF 1000000
using namespace std;

int n;
int color[MAX];//0 表示未进入 -1 表示在之中 1 表示已出去 
int p[MAX];
int M[MAX][MAX];
int d[MAX];

void dijkstra() {
	int i,j,u;
	d[0]=0;
	p[0]=-1;
	while(1) {
		int min=INF;
		u=-1;
		for(i=0;i<n;i++) {
			if(d[i]<min && color[i]!=1) {
				min=d[i];
				u=i;
			}
		}
		if(u==-1) break;
		color[u]=1;
		for(j=0;j<n;j++) {
			if(color[j]!=1 && d[j]>min+M[u][j]) {
				color[j]=-1;
				d[j]=min+M[u][j];
				p[j]=u;
			}
		}
	}
}

int main() {
	memset(d,INF,sizeof(d));
	memset(color,0,sizeof(color));
	memset(p,-1,sizeof(p));
	memset(M,INF,sizeof(M));
	int i,j,u,k,v,c;
	cin>>n;
	for(i=0;i<n;i++) {
		cin>>u>>k;
		for(j=0;j<k;j++) {
			cin>>v>>c;
			M[u][v]=c;
		}
	}
	dijkstra();
	for(i=0;i<n;i++) {
		cout<<i<<' '<<d[i]<<endl;
	}
	return 0;	
}