Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#define MAX 101
#define INF 1000001
using namespace std;

int n, isSelected[MAX], dist[MAX];
vector<pair<int, int>> ver[MAX];

void initDijkstra(void);
void dijkstra(void);
bool doesFinished(void);

int main() {
	int i, j, id, k, v, c;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			ver[id].push_back(make_pair(v, c));
		}
	}

	initDijkstra();

	while (!doesFinished())dijkstra();

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

	return 0;
}

void initDijkstra(void) {

	dist[0] = 0;
	isSelected[0] = 1;
	for (int i = 1; i < n; i++)dist[i] = INF;

	vector<pair<int, int>>::iterator itv;

	for (itv = ver[0].begin(); itv != ver[0].end(); itv++) {
		dist[itv->first] = itv->second;
	}

}

void dijkstra(void) {
	int i, minu, mindist = INF;
	vector<pair<int, int>>::iterator itv;

	for (i = 0; i < n; i++) {
		if (isSelected[i] == 0)continue;
		for (itv = ver[i].begin(); itv != ver[i].end(); itv++){
			if (isSelected[itv->first] == 1)continue;
			if (itv->second < mindist) {
				mindist = itv->second;
				minu = itv->first;
			}
		}
	}
	isSelected[minu] = 1;
	//dist[minu] = dist[minp] + mindist;
	for (itv = ver[minu].begin(); itv != ver[minu].end(); itv++) {
		if (isSelected[itv->first] == 1)continue;
		dist[itv->first] = min(dist[minu] + itv->second, dist[itv->first]);
	}
}

bool doesFinished(void) {
	for (int i = 0; i < n; i++) {
		if (isSelected[i] == 0)return false;
	}
	return true;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
#define INF 1e9
typedef pair<int, int> pi;
int graph[200][200];
int used[200];
int dist[200];
// first:weight, second:key
priority_queue<pi, vector<pi>, greater<pi>> pqueue;

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    dist[i] = INF;
    for (int j = 0; j < n; j++) {
      graph[i][j] = -1;
    }
  }
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    int v, c;
    for (int j = 0; j < k; j++) {
      cin >> v;
      cin >> graph[u][v]; 
    }
  }
  
  pqueue.push(make_pair(0,0));
  dist[0] = 0;
  for (int i = 0; i < n; i++) {
    pi p = pqueue.top();
    pqueue.pop();
    int key = p.second;
    if (used[key] == 1) {
      i--;
      continue;
    }
    dist[key] = min(p.first, dist[key]);
    used[key] = 1;
    for (int j = 0; j < n; j++) {
      if (graph[key][j] != -1 && used[j] != 1) {
        int d = graph[key][j] + dist[key];
        pqueue.push(make_pair(d, j));
      }
    }
  }

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

C++: // http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_12_A
// Graph II - Single Source Shortest Path I
// TODO: REVIEW

#define SUBMIT
//#define DEBUG

#include <utility>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <vector>
#include <limits>
#include <numeric>
#include <functional>
#include <set>
#include <cmath>
#include <cstring>
#include <climits>
#include <memory>

using namespace std;
using ui64 = unsigned long long;
using i64 = long long;

enum class color_type {
    white,
    gray,
    black
};

const int INF = INT_MAX >> 1;
const ui64 MAX_N = 100;
int weight[MAX_N][MAX_N];
int n;

int dijkstra() {
    int d[MAX_N];
    color_type color[MAX_N];

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

    d[0] = 0;
    color[0] = color_type::gray;
    while (true) {
        int u = -1, min_v = INF;
        for (int i = 0; i < n; ++i) {
            if(d[i] < min_v && color[i] != color_type::black) {
                u = i;
                min_v = d[i];
            }
        }

        if (u == -1) break;

        color[u] = color_type::black;
        for (int v = 0; v < n; ++v) {
            if (color[v] != color_type::black && weight[u][v] != INF) {
                if (d[u] + weight[u][v] < d[v]) {
                    d[v] = d[u] + weight[u][v];
                    color[v] = color_type::gray;
                }
            }
        }
    }

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

int main() {
#ifdef SUBMIT
    auto& stream = cin;
#else
    string program_input_str = R"(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
)";
    stringstream stream(program_input_str);
#endif

    stream >> n;
    for (int y = 0; y < n; ++y) {
        for (int x = 0; x < n; ++x) {
            weight[y][x] = INF;
        }
    }

    int u, v, c, degree;
    for (int i = 0; i < n; ++i) {
        stream >> u >> degree;
        for (int d = 0; d < degree; ++d) {
            stream >> v >> c;
            weight[u][v] = c;
        }
    }

#ifdef DEBUG
    for (int y = 0; y < n; ++y) {
        for (int x = 0; x < n; ++x) {
            cout << weight[y][x] << " ";
        }
        cout << endl;
    }
#endif

    dijkstra();
    return 0;
}