Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include<iostream>
int main(){
  int u,k,C,V,D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){     std::cin >> u >> k;
    for(int j=0;j<k;j++){   std::cin >> V >> C;
      D[u][V] = C;}}
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}

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

using namespace std;

class Node {
public:
	int p, d = -1;
};

class Edge {
public:
	int v, u, d;
};

int n, V[100], e = 0;
Edge E[5000];

void Path() {
	V[0] = 0; for (int i = 1; i < n; i++)  V[i] = -1;
	for (int a = 1; a < e; a++) {
		for (int i = 0; i < e; i++) {
			if (V[E[i].u] == -1 && V[E[i].v] != -1 || V[E[i].u] > V[E[i].v] + E[i].d && V[E[i].v] != -1) {
				V[E[i].u] = V[E[i].v] + E[i].d;
			}
		}
	}
}

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

	Path();

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

C++: #include <iostream>
#include <algorithm>
using namespace std;

#define MAX_VERTEX 100
#define INF 1000000

int vertex_num; // ???????????°
int d[MAX_VERTEX][MAX_VERTEX];  // ???????????¢???d[?§????][??????]??§?§??????????????????????????????¢?????¨???

void Input() {
  cin >> vertex_num;

  // (a1) ??\???????????¶??§?????????
  // d?????¨???INF?????????????§??????¨????????????????????´???0
  for (int i = 0; i < vertex_num; i++){
	  for (int j = 0; j < vertex_num; j++){
		  if(i==j){
		  	d[i][j]=0;
		  	}else{
		  	d[i][j]=INF;
		  	}
	  }
  }

  for (int i = 0; i < vertex_num; i++) {
    int vertex, out;
    cin >> vertex >> out;
    for(int j = 0; j < out; j++) {
      int to, c;
      cin >> to >> c;
      d[vertex][to] = c;
    }
  }
}

void WarshallFloyd() {
	// (b1)?§£??¬?????????????????????
	for (int k = 0; k < vertex_num; k++){
		for (int i = 0; i < vertex_num; i++){
			for (int j = 0; j < vertex_num; j++){
				d[i][j] = min(d[i][j],d[i][k]+d[k][j]);
			}
		}

	}
}

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

int main() {

  Input();
  WarshallFloyd();
  Output();

  return 0;
}

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

static const int N = 100;
static const int INF = (1 << 30);
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

int n;
int m[N][N];

void dijkstra(){
    int min_val;
    int d[N],color[N];

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

    //始点設定
    d[0] = 0;
    color[0] = GRAY;

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

        if(u == -1) break;

        color[u] = BLACK;
        for(int v=0;v<n;v++){
            if(color[v] != BLACK && m[u][v] != INF){
                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 << ' ';
        if(d[i] == INF)
            cout << -1;
        else
            cout << d[i];
        cout << endl;
    }

}

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

    dijkstra();

}

C++: #include <iostream>
using namespace std;

const int MAX = 105;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
const int INFTY = (1 << 21);
int n, M[MAX][MAX];
int color[MAX];
int d[MAX];
int p[MAX];

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

  color[root] = GRAY;
  d[root] = 0;

  while (true) {
    int min_cost = INFTY;
    for (int i = 0; i < n; i++) {
      if (color[i] != BLACK && d[i] < min_cost) {
        min_cost = d[i];
        u = i;
      }
    }

    if (min_cost == INFTY) {
      break;
    }

    color[u] = BLACK;

    for (int i = 0; i < n; i++) {
      if (color[i] != BLACK && d[i] > M[u][i] + d[u]) {
        d[i] = d[u] + M[u][i];
        p[i] = u;
        color[i] = GRAY;
      }
    }
  }
}

int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      M[i][j] = INFTY;
    }
  }
  int k, s, t, c;
  for (int i = 0; i < n; i++) {
    cin >> s >> k;
    for (int j = 0; j < k; j++) {
      cin >> t >> c;
      M[s][t] = c;
    }
  }
  dijkstra(0);
  for (int i = 0; i < n; i++) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define REP(i, a, b) for(int i = (a); i < (b); i++)
#define RREP(i, a, b) for(int i = (a); i >= (b); i--)
#define pq priority_queue
#define P pair<int, int>
#define P2 pair<int, P>
#define P3 pair<int, P2>
typedef long long ll; typedef long double ld;
using namespace std;
const int INF = 1e9, MOD = 1e9+7, around[] = {0, 1, 1, -1, -1, 0, -1, 1, 0, 0};
const int vx[] = {1, 0, -1, 0}, vy[] = {0, 1, 0, -1};
const ld PI = abs(acos(-1));
const int sqrtN = 512;
const int logN = 32;
const ll LINF=1e18;

template<typename T>
struct Dijkstra{
	struct edge{
		int to;
		T cost;
	};
	const T INF;
	vector<vector<edge>> g;
	vector<T> min_cost;
	
	Dijkstra(int n) : INF(numeric_limits<T>::max() - numeric_limits<T>::max()/10){
		g.resize(n);
	}
	
	void add_edge(int from, int to, T cost){
		g[from].push_back(edge{to, cost});
	}
	
	vector<T> dijkstra(int s){
		min_cost.assign(g.size(), INF); min_cost[s] = 0;
		pq<pair<T, int>, vector<pair<T, int>>, greater<pair<T, int>>> qu;
		qu.push({0, s});
		
		while(!qu.empty()){
			auto p = qu.top(); qu.pop();
			
			for(auto e:g[p.second]){
				if(p.first + e.cost >= min_cost[e.to]) continue;
				min_cost[e.to] = p.first + e.cost;
				qu.push({min_cost[e.to], e.to});
			}
		}
		
		return min_cost;
	}
};


int main(){
	int n; cin >> n;
	Dijkstra<ll> dijk(n);
	for(int i = 0; i < n; i++){
		int k; cin >> k >> k;
		
		for(int j = 0; j < k; j++){
			int a, b; cin >> a >> b;
			dijk.add_edge(i, a, (ll)b);
			dijk.add_edge(a, i, (ll)b);
		}
	}
	
	vector<ll> min_cost = dijk.dijkstra(0);
	for(int i = 0; i < n; i++) cout << i << " " << min_cost[i] << endl;
	return 0;
}