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>
#include<vector>
#include<queue>
using namespace std;
struct Edge {
    int d, i, j;
    Edge(int d_, int i_, int j_) : d(d_), i(i_), j(j_) {}
    bool operator< (const Edge& right) const{
        return d > right.d;
    }
};
void calc(int t, vector<vector<int> >& G, vector<int>& distance){
    int new_black = t;
    priority_queue<Edge> temp;
    for (int i = 1; i < G.size(); i++) {
        for (int j = 0; j < G.size(); j++) {
            if (distance[j] != -1) continue;
            int dis = G[new_black][j] + distance[new_black];
            temp.push(Edge(dis, new_black, j));
        }
        while (distance[temp.top().j] != -1) temp.pop();
        distance[temp.top().j] = temp.top().d;
        new_black = temp.top().j;
        temp.pop();
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n, vector<int>(n, 1e8));
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int c, v;
            cin >> c >> v;
            G[u][c] = v;
        }
    }

    vector<int> distance(n, -1);
    distance[0] = 0;
    calc(0, G, distance);
    for (int i = 0; i < n; i++) {
        cout << i << " " << distance[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
static const int M=10000;
static const int INF=(1<<20);
int n;
vector<pair<int,int > > a[M];
void dijkstra(){
	priority_queue<pair<int,int> > Q;
	int col[M];
	int d[M];
	for(int i=0;i<n;i++){
		col[i]=0;
		d[i]=INF;
	}
	d[0]=0;col[0]=1;
	Q.push(make_pair(0,0));
	while(!Q.empty()){
		pair<int,int>f=Q.top();Q.pop();
		int u=f.second;col[u]=2;
		if(d[u]<f.first*(-1))continue;
		for(int j=0;j<a[u].size();j++){
			int v=a[u][j].first;
			if(col[v]==2)continue;
			if(d[v]>d[u]+a[u][j].second){
				d[v]=d[u]+a[u][j].second;
				Q.push(make_pair(d[v]*(-1),v));
				col[v]=1;
			}
		}
	}
	for(int i=0;i<n;i++)cout<<i<<' '<<(d[i]==INF?-1:d[i])<<endl;
}
int main() {
	int k,u,v,c;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>v>>c;
			a[u].push_back(make_pair(v,c));
		}
	}
	dijkstra();
}

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

int flg[100];

bool check(int p){

	if (flg[p] == 1) return false;
	return true;
}

int main(void){

	int n;

	cin >> n;
	int u, k;
	int date[100][100]; //date[??????????????????][?????´?????????]
	int dis[100]; //0????????????????????????????????¢

	memset(date, INF, sizeof(date));
	memset(dis, INF, sizeof(dis));
	memset(flg, 0, sizeof(flg));
	date[0][0] = 0;
	dis[0] = 0;
	for (int i = 0; i < n; i++){

		cin >> u >> k;
		for (int j = 0; j < k; j++){

			int v, c;
			cin >> v >> c;
			date[u][v] = c;
		}
	}

	while(1){
		int mini = INF;
		int p = -1;
		for (int i = 0; i < n; i++){
			if (check(i) && mini > dis[i]){
				p = i;
				mini = dis[i];
			}
		}
		if (p == -1) break;
		flg[p] = 1;
		for (int i = 0; i < n; i++){
			if (check(i) && dis[i] > dis[p] + date[p][i]){
				dis[i] = dis[p] + date[p][i];
			}
		}
	}

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

C++: #include <algorithm>
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
#define ld long double
#define INF 1000000000000000000
typedef pair<ll, ll> pll;
typedef pair<int, int> pint;

struct edge {
    ll to;
    ll cost;
};

int N;
vector<vector<edge>> G;
vector<ll> d(150);

void dijkstra() {
    d.assign(N, INF);
    d[0] = 0;
    vector<bool> seen(N, false);
    while (true) {
        ll minv = INF;
        int v = -1;
        rep(i, N) {
            if (!seen[i] && minv > d[i]) {
                v = i;
                minv = d[i];
            }
        }

        if (v == -1)
            break;
        seen[v] = true;
        for (int i = 0; i < G[v].size(); i++) {
            edge e = G[v][i];
            if (seen[e.to])
                continue;
            if (d[e.to] > d[v] + e.cost) {
                d[e.to] = d[v] + e.cost;
            }
        }
    }
}

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

    cin >> N;
    G.resize(N);
    rep(i, N) {
        ll a, b;
        cin >> a >> b;
        rep(j, b) {
            ll c, d;
            cin >> c >> d;
            G[a].push_back({c, d});
        }
    }

    dijkstra();
    rep(i, N) { cout << i << " " << d[i] << endl; }
}

C++: #include <iostream>

#define N_MAX 101
#define INF 100000000

using namespace std;

int main(){
  int n; cin >> n;
  int G[n][n];
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      G[i][j]=-1;
    }
  }
  for(int i=0;i<n;i++){
    int u,k; cin >> u >> k;
    for(int i=1;i<=k;i++){
      int v,c; cin >> v >> c;
      G[u][v]=c;
    }
  }
  //dijkstra's algorithm
  int visited[n],d[n];
  for(int i=0;i<n;i++){
    visited[i]=0;
    d[i]=INF;
  }
  d[0]=0;

  while(1){
    int mind=INF;
    int u;
    for(int i=0;i<n;i++){
      if(visited[i]==0 && d[i]<mind){
        mind=d[i];
        u=i;
      }
    }
    if(mind==INF) break;
    visited[u]=1;
    for(int v=0;v<n;v++){
      if(G[u][v]!=-1 && visited[v]==0){
        if(d[u]+G[u][v]<d[v]) d[v]=d[u]+G[u][v];
      }
    }
  }
  for(int i=0;i<n;i++) cout << i << " " << d[i] << endl;
}