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 <iostream>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
using namespace std;

typedef long long ll;

#define MAX_V 100
#define INF int(1e9)

struct Edge {
    int v, cost;
    Edge() {}
    Edge(int v, int cost) : v(v), cost(cost) {}
};

// g[] : ????????????????????°???????????£??\?????????, V : ????????°, s : ?§??????¨????????????, d[] : s????????????????????????????´?????????????
int Dijkstra (vector<Edge> g[], int V, int s, int d[]) {
    priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > que;
    fill(d, d + V, INF);
    d[s] = 0;
    que.push(make_pair(0, s)); // pair(cost, vertex)

    while (!que.empty()) {
        pair<int, int> p = que.top();
        que.pop();
        int v = p.second, size_ = g[v].size();

        if (d[v] < p.first) continue;

        for (int i = 0; i < size_; ++i) {
            Edge e = g[v][i];
            if (d[e.v] > d[v] + e.cost) {
                d[e.v] = d[v] + e.cost;
                que.push(make_pair(d[e.v], e.v));
            }
        }
    }

}

int n, u, k, v, c, d[MAX_V + 1];
vector<Edge> g[MAX_V + 1]; // ????????°??????

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

    cin >> 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(Edge(v, c));
        }
    }

    Dijkstra(g, n, 0, d);

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

    return 0;
}

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[100];
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);
    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<bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i) 
#define PI acos(-1)

using namespace std;
using ll = long long;
using P = pair<int, int>;
using LP = pair<ll, ll>;

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

    int n;
    cin>>n;
    vector<vector<P>> adj(n);
    rep(i, n) {
        int u, k, v, c;
        cin>>u>>k;
        rep(j, k) {
            cin>>v>>c;
            adj[u].push_back(P(c, v));
        }
    }

    priority_queue<P, vector<P>, greater<P>> q;
    vector<int> wmap(n, -1);
    q.push(P(0, 0));
    while (!q.empty()) {
        P p = q.top(); q.pop();
        int w = p.first;
        int v = p.second;
        if (wmap[v] != -1) continue;

        wmap[v] = w;
        for (auto e : adj[v]) {
            q.push(P(e.first + w, e.second));
        }
    }

    rep(i, n) cout<<i<<" "<<wmap[i]<<endl;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <numeric>
#include <climits>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;
static const int INF = INT_MAX;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

static const int N = 2010;
int M[N][N];
int color[N];
int d[N];
int p[N];
int n;

void dijkstra(int s) {
  rep(u, n) {
    color[u] = WHITE;
    d[u] = INF;
  }
  d[s] = 0;
  p[s] = -1;

  while (true) {
    int mincost = INF;
    int u;
    rep(i, n) {
      if (color[i] != BLACK && d[i] < mincost) {
        mincost = d[i];
        u = i;
      }
    }

    if (mincost == INF) break;

    color[u] = BLACK;

    rep(v, n) {
      if (color[v] != BLACK && M[u][v] != INF) {
        if (d[u] + M[u][v] < d[v]) {
          d[v] = d[u] + M[u][v];
          p[v] = u;
          color[v] = GRAY;
        }
      }
    }
  }
}

int main() {
  cin >> n;
  rep(y, n) rep(x, n) {
    M[y][x] = INF;
  }
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int v, c;
      cin >> v >> c;
      M[u][v] = c;
    }
  }
  dijkstra(0);
  rep(v, n) cout << v << " " << d[v] << endl;
  return 0;
}