Go: // ダイクストラのアルゴリズム
package main

import (
	"bufio"
	"fmt"
	"log"
	"math"
	"os"
	"strconv"
	"strings"
)

type color int

const (
	white color = iota // 未訪問
	mst                // MSTとして確定
)

// 頂点
type node struct {
	num       int         // 頂点の番号
	weights   map[int]int // 重みMAP
	parent    *node       // MSTへの重み最小の親
	distFromS int         // 始点からの距離
	color     color
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	n := eGetInt(scanner)

	nodes := make([]*node, n)
	for i := 0; i < n; i++ {
		weights := eAtoi((strings.Fields(eGetline(scanner))))
		v := &node{weights[0], make(map[int]int, weights[1]), nil, math.MaxInt32, white}
		for j := 0; j < weights[1]; j++ {
			k := weights[j*2+2] // 相手の頂点名
			w := weights[j*2+3] // 重み
			v.weights[k] = w
		}
		nodes[i] = v
	}

	// 初回はnode[0]がMSTに入るように
	nodes[0].distFromS = 0

	for { // 全部チェックするまで

		// どの頂点を新たにMSTに取り込むか

		var minNode *node
		min := math.MaxInt32
		for _, v := range nodes {
			if v.color == mst {
				continue
			}
			if v.distFromS < min {
				min = v.distFromS
				minNode = v
			}
		}
		if minNode == nil {
			// すべて完了している.
			break
		}

		// MSTに追加する頂点決定
		minNode.color = mst

		// fmt.Printf(">[%v]\n", minNode)
		// MSTに属していない頂点それぞれについて,Startからの最小の重みの距離を更新
		for i, v := range nodes {
			if v.color == mst {
				continue
			}
			w, ok := minNode.weights[i]
			if !ok {
				// minNodeと接してない
				continue
			}

			if minNode.distFromS+w < v.distFromS {
				// minNode経由の距離がもっとも重みが少ないので親を変更
				v.distFromS = minNode.distFromS + w
				v.parent = minNode
				// fmt.Printf("[%v %v]\n", v, minNode)
			}
		}
		// fmt.Printf("<\n")
	}

	for i, v := range nodes {
		fmt.Printf("%d %d\n", i, v.distFromS)
	}
}

func eGetInt(scanner *bufio.Scanner) int {
	t := eAtoi(strings.Fields(eGetline(scanner)))
	return t[0]
}

func eGetline(p *bufio.Scanner) string {
	if !p.Scan() {
		if err := p.Err(); err != nil {
			log.Fatal(err.Error())
		}
		return ""
	}
	return p.Text()
}

func eAtoi(s []string) []int {
	ints := make([]int, len(s))
	var err error
	for i, e := range s {
		ints[i], err = strconv.Atoi(e)
		if err != nil {
			log.Fatal(err.Error())
		}
	}
	return ints
}

C++: #include <cstdio>
#include <cstdint>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>
#include <cinttypes>

#include <memory>
#include <queue>
#include <map>
#include <unordered_map>
using namespace std;

#define NDEBUG
#define MYDEBUG (0)

#if MYDEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // MYDEBUG


const int kMaxVertex = 10 * 1000;
const int kMaxWeight = 100 * 1000;
const int kMaxNumPath = 500 * 1000;
const int kInvalidWeight = -1;

int g_num_of_vertex;
int g_min_weight[kMaxVertex];


/*
   2D data structure ([x][y] = value)
*/
struct DstAndWeight {
    int dst_;
    int weight_;
};

struct StartIdxAndLen {
    int start_;
    int len_;
};

class WeightGraph {
public:
    WeightGraph()
    {
        end_weights_ = 0;
        end_idx_len_ = 0;

        const int n = kMaxNumPath;
        weights_ = unique_ptr<DstAndWeight[]>(new DstAndWeight[n]);

        DPRINTF("allocated weights_ ptr (%lu bytes)\n", sizeof(weights_));

        const int n2 = kMaxVertex;
        idx_len_ = unique_ptr<StartIdxAndLen[]>(new StartIdxAndLen[n2]);

        for (int i = 0; i < n2; i++)
        {
            idx_len_[i].start_ = -1;
            idx_len_[i].len_ = -1;
        }

        DPRINTF("allocated idx_len_ ptr (%lu bytes)\n", sizeof(idx_len_));
    }

    void setWeight(int from, const vector<int> &tos, const vector<int> &weights);
    int getWeight(int from, int to) const;
    vector<int> getConnectedVertices(int from) const;

private:
    inline int getLen(int v) const { return idx_len_[v].len_; }
    inline int getStartIdx(int v) const { return idx_len_[v].start_; }

    unique_ptr<DstAndWeight[]> weights_;
    unique_ptr<StartIdxAndLen[]> idx_len_;

    uint32_t end_weights_;
    uint32_t end_idx_len_;
};


void WeightGraph::setWeight(int from, const vector<int> &tos, const vector<int> &weights)
{
    assert(0 <= from && from < kMaxNumPath);
    assert(tos.size() == weights.size());
    assert(end_weights_ + tos.size() < kMaxNumPath);

    idx_len_[from].start_ = end_weights_;
    idx_len_[from].len_ = tos.size();

    for (int i = 0; i < tos.size(); i++)
    {
        weights_[end_weights_].dst_ = tos[i];
        weights_[end_weights_].weight_ = weights[i];
        end_weights_++;
    }

    end_idx_len_++;

}


int WeightGraph::getWeight(int from, int to) const
{
    const int start = getStartIdx(from);
    const int len = getLen(from);

    assert(0 <= start);
    assert(start + len <= end_weights_);

    for (int i = start; i < start + len; i++)
    {
        if (weights_[i].dst_ == to)
            return weights_[i].weight_;
    }

    return kInvalidWeight;
}

///////////////////////////////////////////////////
struct Edge {
    Edge(int num_vertex)
        : num_vertex_(num_vertex)
    {
        graph_ = new WeightGraph();
    }

    ~Edge()
    {
        delete graph_;
    }

    bool isConnected(int from, int to) const;
    vector<int> getConnectedVertices(int v) const;
    int getWeight(int from, int to) const;
    void setWeight(int from, const vector<int> &tos, const vector<int> &weights);
    void printWeight() const;

    int num_vertex_;

    WeightGraph *graph_;
};

bool Edge::isConnected(int from, int to) const
{
    if (from == to)
        return false;

    if (getWeight(from, to) == kInvalidWeight)
        return false;

    return true;
}

vector<int> Edge::getConnectedVertices(int v) const
{
    vector<int> vertices;

    for (int i = 0; i < num_vertex_; i++)
        if (isConnected(v, i))
            vertices.push_back(i);

    return vertices;
}

void Edge::setWeight(int from, const vector<int> &tos, const vector<int> &weights)
{
    assert(0 <= from && from < num_vertex_);
    for (const int t : tos)       assert(0 <= t && t < kMaxVertex && t < num_vertex_);
    for (const int w : weights)   assert(0 <= w && w < kMaxWeight);

    graph_->setWeight(from, tos, weights);
}

int Edge::getWeight(int from, int to) const
{
    return graph_->getWeight(from, to);
}

void Edge::printWeight() const
{
    for (int i = 0; i < num_vertex_; i++)
    {
        DPRINTF("%d:", i);

        for (int j = 0; j < num_vertex_; j++)
        {
            const int w = graph_->getWeight(i, j);
            if (w != kInvalidWeight)        printf(" %d", w);
            else                            printf(" -");
        }
        cout << endl;

    }
}


//////////////////////////////////////////////////////////////
struct VtxAndWeight {
    VtxAndWeight(int vtx, int weight)
        : vtx_(vtx)
        , weight_(weight)
    {}

    int vtx_;
    int weight_;

    bool operator>(const VtxAndWeight& rhs)
    {
        return (*this).weight_ > rhs.weight_;
    };

    bool operator<(const VtxAndWeight& rhs)
    {
        return (*this).weight_ < rhs.weight_;
    };
};

struct LessThanByWeight
{
    bool operator()(const VtxAndWeight& lhs, const VtxAndWeight& rhs) const
    {
        return lhs.weight_ > rhs.weight_;
    }

};


/* Dijkstra's algorithm */
void calcShortestPath(int start, const Edge &edge)
{
    priority_queue<VtxAndWeight, vector<VtxAndWeight>, LessThanByWeight> priority_queue;

    const int init_weight = 0;
    g_min_weight[start] = 0;
    priority_queue.push(VtxAndWeight(start, init_weight));

    while (!priority_queue.empty())
    {
        // select the minimum weight from the priority queue
        const int vtx = priority_queue.top().vtx_;
        const int weight = priority_queue.top().weight_;
        priority_queue.pop();

        DPRINTF("vtx %d  weight %d\n", vtx, weight);

        if (weight > g_min_weight[vtx])
            continue;

        // find connected vertices
        vector<int> connectedVertices = edge.getConnectedVertices(vtx);

        // update min weight for the vertices
        for (int neighbour : connectedVertices)
        {
            const int updated_weight= weight + edge.getWeight(vtx, neighbour);

            if (updated_weight < g_min_weight[neighbour])
            {
                g_min_weight[neighbour] = updated_weight;
                priority_queue.push(VtxAndWeight(neighbour, g_min_weight[neighbour]));
            }

            DPRINTF("g_min_weight[%d] %d\n", neighbour, g_min_weight[neighbour]);
        }
    }

}


int main()
{
    cin >> g_num_of_vertex;
    cin.ignore();

    assert(kMaxVertex >= g_num_of_vertex);

    // init
    for (int i = 0; i < g_num_of_vertex; i++)
    {
        g_min_weight[i] = INT_MAX;
    }

    Edge edge(g_num_of_vertex);

    // input
    for (int i = 0; i < g_num_of_vertex; i++)
    {
        int from, degree;
        cin >> from >> degree;

        vector<int> tos, weights;

        for (int j = 0; j < degree; j++)
        {
            int to, weight;
            cin >> to >> weight;

            tos.push_back(to);
            weights.push_back(weight);

        }
        cin.ignore();

        edge.setWeight(from, tos, weights);
    }

#if MYDEBUG
    edge.printWeight();
#endif // MYDEBUG

    // process
    const int start = 0;
    calcShortestPath(start, edge);

    // output
    for (int i = 0; i < g_num_of_vertex; i++)
        printf("%d %d\n", i, g_min_weight[i]);

    return 0;
}