Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include <iostream>
#include <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>
#include <algorithm>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

class path{
public:
    int from;
    int to;
    int dist;
    path(){
        from = -1;
        to = -1;
        dist = -1;
    }
    path(int from_,int to_,int dist_){
        from = from_;
        to = to_;
        dist = dist_;
    }
    static bool compare(const path& a,const path& b) {
        return a.from < b.from;
    }
    bool operator<(const path& e) const {
        return this->dist < e.dist;
    }
};

int n,u,k,v,c;
vector<path> w;
ll d[10000];

int main() {
    for(int i = 0;i < 10000;i++)d[i] = -NIL;
    cin >> n;
    for(int i = 0;i < n;i++) {
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v >> c;
            w.push_back(path(u,v,c));
        }
    }
    sort(w.begin(),w.end(),path::compare);
    priority_queue<pair<int,int>> q;
    q.push(make_pair(0,0));
    d[0] = 0;
    while(!q.empty()) {
        auto y = q.top();q.pop();
        if(d[y.second] != y.first) continue;
        auto r = lower_bound(w.begin(),w.end(),path(y.second,0,0),path::compare);
        auto l = lower_bound(w.begin(),w.end(),path(y.second+1,0,0),path::compare);
        for(auto itr = r;itr < l;itr++) {
            if(d[itr->to] > d[itr->from] + itr->dist) {
                d[itr->to] = d[itr->from] + itr->dist;
                q.push(make_pair(d[itr->to],itr->to));
            }
        }
    }
    for(int i = 0;i < n;i++){
        cout << i << " " << d[i] << endl;
    }
}

C++: #include <algorithm>
#include <bitset>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

void dijkstra(vector<vector<pair<int, int>>>& edges, vector<int>& ds, int start) {
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
    q.push(make_pair(0, start));
    while (!q.empty()) {
        int d = q.top().first;
        int u = q.top().second;
        q.pop();
        if (ds[u] >= 0) {
            continue;
        }
        ds[u] = d;
        for (auto p : edges[u]) {
            q.push(make_pair(d + p.second, p.first));
        }
    }
}

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

    vector<int> ds(n, -1);
    dijkstra(edges, ds, 0);

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

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxx=1010;
const int infinity=1<<30;
int A[maxx][maxx],d[maxx];
bool flag[maxx];
int n,a,b,c;
	
int main (){
	cin>>n;
	for(int i=0;i<n;i++){
		flag[i]=false;
		d[i]=infinity;
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			A[i][j]=infinity;
		}
	}
	for(int i=0;i<n;i++){
		cin>>a>>b;
		for(int j=0;j<b;j++){
			cin>>c;
			cin>>A[a][c];
		}
	}
	d[0]=0;
	while(1){
		int minv=infinity,minj=-1;
		for(int i=0;i<n;i++){
			if(flag[i]==false && d[i]<minv){
				minv=d[i];
				minj=i;
			}
		}
		if(minv==infinity) break;
		flag[minj]=true;
		for(int i =0;i<n;i++){
			if(A[minj][i]!=infinity && flag[i]==false && d[i]>=d[minj]+A[minj][i]){
					d[i]=d[minj]+A[minj][i];
			}
		}
	}
	for(int i=0;i<n;i++) cout<<i<<" "<<(d[i]==infinity ? -1 : d[i])<<endl;
	
	return 0;

}

C++: #include<iostream>
using namespace std;
const int MAX = 100;
const int INFTY = (1<<21);
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

int n,M[MAX][MAX];

void dijkstra(){
    int minv;
    int d[MAX],color[MAX];

    for (int i = 0; i < n ; ++i) {
        d[i] = INFTY;
        color[i] = WHITE;
    }

    d[0] = 0;
    color[0] = GRAY;
    while(1){
        minv = INFTY;
        int u = -1;
        for (int i = 0; i < n ; ++i) {
            if( minv > d[i] && color[i] != BLACK){
                u = i;
                minv = d[i];
            }
        }
        if(u == -1) break;
        color [u] = BLACK;
        for (int v = 0; v < n ; ++v) {
            if(color[v] != BLACK && M[u][v] != INFTY){
                if(d[v] > d[u] + M[u][v]){
                    d[v] = d[u] + M[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }
    for (int i = 0; i < n ; ++i) {
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}

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

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 1000000000

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

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

  vector<int> d(n,MAX);
  vector<bool> used(n, false);
  d[0] = 0;
  while(true){
    int t = -1;
    for(int i = 0; i < n; i++){
      if(!used[i] && (t == -1 || d[t] > d[i])) t = i;
    }
    if(t == -1) break;
    used[t] = true;

    for(int i = 0; i < n; i++){
      d[i] = min(d[i], d[t] + f[t][i]);
    }
  }

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