Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

const (
	MAX_N      = 10000
	MAX_WEIGHT = 100000
)

type Edge struct {
	start  int
	end    int
	weight int
}

type ShortestInfo struct {
	edges    []Edge
	shortest int
}

type Neighbor struct {
	node   int
	weight int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	shortestList := make([]ShortestInfo, n)
	for i := 1; i < n; i++ {
		shortestList[i] = ShortestInfo{edges: []Edge{}, shortest: MAX_N*MAX_WEIGHT + 1}
	}

	adjacentMatrix, err := createAdjacentMatrix(n, sc)
	if err != nil {
		panic(err)
	}

	sssp([]int{0}, shortestList, adjacentMatrix)
	for _, v := range shortestList {
		fmt.Printf("%d %d\n", v.getEnd(), v.shortest)
	}
}

func (si ShortestInfo) getEnd() int {
	if len(si.edges) == 0 {
		return 0
	} else {
		return si.edges[len(si.edges)-1].end
	}
}

func createAdjacentMatrix(n int, sc *bufio.Scanner) ([][]Neighbor, error) {
	adjacentMatrix := make([][]Neighbor, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		adjacentMatrix[id] = []Neighbor{}
		vertexNum, err := nextInt(sc)
		if err != nil {
			return nil, err
		}
		for j := 0; j < vertexNum; j++ {
			v, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			c, err := nextInt(sc)
			if err != nil {
				return nil, err
			}
			adjacentMatrix[id] = append(adjacentMatrix[id], Neighbor{v, c})
		}
	}
	return adjacentMatrix, nil
}

func sssp(nodeStack []int, shortestList []ShortestInfo, adjacentMatrix [][]Neighbor) {
	for len(nodeStack) > 0 {
		currentNode := nodeStack[0]
		nodeStack = nodeStack[1:]
		currentShortest := getShortest(currentNode, shortestList)
		adjacents := findAdjacents(currentNode, adjacentMatrix)
		for i := 0; i < len(adjacents); i++ {
			adj := adjacents[i]
			if currentShortest.shortest+adj.weight < getShortest(adj.end, shortestList).shortest {
				setShortest(adj.end, adj, currentShortest, shortestList)
				nodeStack = append(nodeStack, adj.end)
			}
		}
	}
}

func getShortest(node int, shortestList []ShortestInfo) ShortestInfo {
	return shortestList[node]
}

func setShortest(node int, edge Edge, currentShortest ShortestInfo, shortestList []ShortestInfo) {
	newEdges := make([]Edge, len(currentShortest.edges)+1)
	for i := 0; i < len(newEdges)-1; i++ {
		newEdges[i] = currentShortest.edges[i]
	}
	newEdges[len(newEdges)-1] = edge
	shortestInfo := ShortestInfo{edges: newEdges, shortest: currentShortest.shortest + edge.weight}
	shortestList[node] = shortestInfo
}

func findAdjacents(currentNode int, adjacentMatrix [][]Neighbor) []Edge {
	adjacents := adjacentMatrix[currentNode]
	edges := []Edge{}
	for _, neighbor := range adjacents {
		edges = append(edges, Edge{start: currentNode, end: neighbor.node, weight: neighbor.weight})
	}
	return edges
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <limits>
#include <cmath>
#include <numeric>
#include <string>
#include <queue>

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
#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 REP(i, a, b) for(int i = (a); i <= (b); ++i )
#define RREP(i, a, b) for(int i = (a); i >= (b); --i )
#define llrep(i, a, b) for(ll i = (a); i < (b); ++i )
#define llrrep(i, a, b) for(ll i = (a); i > (b); --i )
#define llREP(i, a, b) for(ll i = (a); i <= (b); ++i )
#define llRREP(i, a, b) for(ll i = (a); i >= (b); --i )
#define ullrep(i, a, b) for(ull i = (a); i < (b); ++i )
#define ullrrep(i, a, b) for(ull i = (a); i > (b); --i )
#define ullREP(i, a, b) for(ull i = (a); i <= (b); ++i )
#define ullRREP(i, a, b) for(ull i = (a); i >= (b); --i )

template<typename T=int>
class UnionFind {
public:
    explicit UnionFind(unsigned long long n) : rank_(n, 0), p_(n, 0) {
        for (T i = 0; i < n; i++) {
            MakeSet(i);
        }
    }

    void MakeSet(T x) {
        p_[x] = x;
        rank_[x] = 0;
    }

    bool Same(T x, T y) {
        return FindSet(x) == FindSet(y);
    }

    void Link(T x, T y) {
        if (rank_[x] > rank_[y]) {
            p_[y] = x;
        } else {
            p_[x] = y;
            if (rank_[x] == rank_[y]) {
                rank_[y]++;
            }
        }
    }

    void Unite(T x, T y) {
        Link(FindSet(x), FindSet(y));
    }

    T FindSet(T x) {
        if (x != p_[x]) {
            p_[x] = FindSet(p_[x]);
        }
        return p_[x];
    }

private:
    std::vector<T> rank_, p_;
};

// 隣接行列を使ったダイクストラ
class Dijkstra {
public:
    Dijkstra(unsigned long long num, int max_cost) :
            num_(num),
            max_cost_(max_cost),
            v_(num, std::vector<int>(num, max_cost)),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0) {
    };

    void Compute(int start) {
        d_[start] = 0;
        p_[start] = start;
        while (true) {
            int m = -1;
            int min_d = std::numeric_limits<int>::max();
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (min_d > d_[i])) {
                    min_d = d_[i];
                    m = i;
                }
            }
            if (m < 0) {
                break;
            }
            c_[m] = 1;
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (d_[i] > (d_[m] + v_[m][i])) ) {
                    d_[i] = d_[m] + v_[m][i];
                    p_[i] = m;
                }
            }
        }
    }

public:
    int num_;
    int max_cost_;
    std::vector<std::vector<int>> v_;
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<int> p_;
};

class DijkstraQueue {
public:
    DijkstraQueue(unsigned long long num, int max_cost):
            num_(num),
            adj_(num),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0)
    {}

    void Compute(int start) {
        std::priority_queue<std::pair<int, int>> pq;
        d_[start] = 0;
        pq.push(std::make_pair(0, start));
        while (!pq.empty()) {
            auto f = pq.top();// cost, i
            pq.pop();
            int u = f.second;
            c_[u] = 1;
            if (d_[u] < f.first * (-1)) {
                continue;
            }

            for(int j = 0; j < adj_[u].size(); j++) {
                int v = adj_[u][j].first;
                if (c_[v] == 1) continue;
                if (d_[v] > d_[u] + adj_[u][j].second) {
                    d_[v] = d_[u] + adj_[u][j].second;
                    pq.push(make_pair(d_[v] * (-1), v));
                }
            }
        }
    }
    int num_;
    std::vector<std::vector<std::pair<int, int>>> adj_; //i, cost
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<int> p_;
};




int N, Q;

int G[100][100];
int d[100];
int p[100];
int c[100];

int main() {
    cin >> N;
//    rep(i, 0, N) {
//        rep(j, 0, N) {
//            G[i][j] = 10000010;
//        }
//    }
//    Dijkstra dj(N, 10000010);
    DijkstraQueue dj(N, 10000010);
    rep(i, 0, N) {
        int u, k;
        cin >> u >> k;
        rep(j, 0, k) {
            int t, d;
            cin >> t >> d;
            dj.adj_[u].push_back(make_pair(t, d));
        }
    }
    dj.Compute(0);
    rep(i, 0, N) {
        cout << i << " " << dj.d_[i] << endl;
    }
}