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 <stdio.h>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1<<21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[MAX][MAX];
int d[MAX];

void dijkstra(int s) {
    int p[n];
    int color[n];
    
    for(int i=0; i<n; i++) {
        color[i] = WHITE;
        d[i] = INFTY;
        p[i] = -1;
    }
    
    d[s] = 0;
    
    while(1) {
        int u;
        int mincost = INFTY;
        for (int i=0; i<n; i++) {
            if (color[i] != BLACK && d[i] < mincost) {
                mincost = d[i];
                u = i;
            }
        }
        
        if (mincost == INFTY) break;
        
        color[u] = BLACK;
        
        for (int v=0; v<=n; v++) {
            if (color[v] != BLACK && M[u][v] != INFTY) {
                if(d[u] + M[u][v] < d[v]) {
                    d[v] = d[u] + M[u][v];
                    p[v] = u;
                    color[v] = GRAY;
                }
            }
        }
    }
}

int main() {
    scanf("%d", &n);
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            int tmp;
            scanf("%d", &tmp);
            M[i][j] = (tmp == -1) ? INFTY : tmp;
        }
    }
    
    dijkstra(0);
    
    for(int i=0; i<n; i++) {
        printf("%d %d\n", i, d[i]);
    }
    
    return 0;
}

C++: #include <iostream>
#include <cstring>
#define MAX 120000
using namespace std;

int matrix[105][105],n,closest[105],close[105];

void djst(){
    int i,j,k;
    for(i=1;i<n;i++){
        if(matrix[0][i]!=-1)close[i]=matrix[0][i];
    }
    while(1){
        int mi=MAX,rec=-1;
        for(i=1;i<n;i++){
            if(close[i]!=-1&&close[i]<mi&&closest[i]==-1){
                mi=close[i];
                rec=i;
            }
        }
        if(rec==-1)break;
        closest[rec]=mi;
        close[rec]=MAX;
        for(j=1;j<n;j++){
            if(closest[j]==-1&&matrix[rec][j]!=-1){
                if(mi+matrix[rec][j]<close[j]||close[j]==-1)close[j]=mi+matrix[rec][j];
            }
        }
    }
}
int main(){
    memset(close,-1,sizeof(close));//memset??????????????¨0???-1???????????°???????§????
    memset(closest,-1,sizeof(closest));
    memset(matrix,-1,sizeof(matrix));
    int i,j;
    cin>>n;
    for(i=0;i<n;i++){
        int a,b;
        cin>>a>>b;
        for(j=0;j<b;j++){
            int c,d;
            cin>>c>>d;
            matrix[a][c]=d;
        }
    }
    closest[0]=0;
    djst();
    for(i=0;i<n;i++){
        cout<<i<<" "<<closest[i]<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#define N 100
#define INF (1<<30)
using namespace std;

int n, M[N][N], d[N], color[N] = {0};

void Dijk(int s) {
	int min;
	for (int i = 0;i < n;i++) d[i] = INF;
	d[s] = 0;
	while (true) {
		int u=-1;
	    min = INF;
		for (int i = 0;i < n;i++) {
			if (color[i] == 0 && d[i] < min)
				min = d[i];
			    u = i;
		}

		if (u==-1) break;

		color[u] = 1;

		for (int v = 0;v < n;v++) {
			if (color[v] == 0 && M[u][v] != INF)
				if (d[v] > d[u] + M[u][v]) {
					d[v] = d[u] + M[u][v];
				}
		}
	}

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

}

int main() {

	for (int i = 0;i < N;i++)
		for (int j = 0;j < N;j++) M[i][j] = INF;

	cin >> n;
	for (int i = 0;i < n;i++) {
		int u,v;
		cin >> u;
		int k;
		cin >> k;
		for (int j = 0;j < k;j++) {
			cin >> v;
			cin >> M[u][v];
		}
	}

	Dijk(0);

}

C++: #include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
const ll inf=99999999999999999;
#define rep(i,t,n) for(int i=t;i<n;i++)
const int maxn=1e2+7;
ll d[maxn][maxn];
int main(){
    int a,n,m,x;ll z;
    scanf("%d",&n);
    rep(i,0,n) rep(j,0,n) d[i][j]=inf;
    rep(i,0,n) d[i][i]=0;
    rep(i,0,n){
        scanf("%d%d",&a,&m);
        rep(j,0,m){
            scanf("%d%lld",&x,&z);
            d[a][x]=min(d[a][x],z);
        }
    }
    if(n==1){
        printf("0 0\n");
        return 0;
    }
    rep(k,0,n) rep(i,0,n) rep(j,0,n) d[i][j]=min(d[i][j],d[i][k]+d[k][j]);
    rep(i,0,n) printf("%d %lld\n",i,d[0][i]);
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;

struct Edge {
    ll t,w;
};

struct State {
    ll v;
    ll score;
    bool operator < (const State& tgt) const {
	return score > tgt.score;
    }
};

vector<ll> dijkstra(vector<vector<Edge>>& G, const int start) {
    const ll V = G.size();

    vector<ll>res(V,INT_MAX);
    priority_queue<State> q;
    q.push( State{0,0} );
    while( q.size() ) {
	State s = q.top(); q.pop();
	if( res[s.v] != INT_MAX ) continue;
	res[s.v] = s.score;
	for(auto& e : G[s.v]) {
	    if( res[e.t] != INT_MAX ) continue;
	    q.push( State{e.t, s.score + e.w} );
	}
    }
    return res;
}


int main () {

    ll V; cin >> V;
    vector<vector<Edge>> G(V);
    for(int i=0; i<V; i++) {
	ll u,k; cin >> u >> k;
	for(int j=0; j<k; j++) {
	    ll v,w; cin >> v >> w;
	    G[i].push_back( Edge{v,w} );
	}
    }
    vector<ll> res = dijkstra(G,0);
    for(int i=0; i<V; i++) {
	cout << i << " " << res[i] << endl;
    }    
    return 0;
}