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 <queue>
#include <vector>

using namespace std;

#define INF (10000001)

typedef pair<int, int> Edge;

int main()
{
    priority_queue<Edge,vector<Edge>,greater<Edge> > pq;
    vector<vector<Edge> > e;
    vector<int> d;
    Edge etemp;
    int n,u,k,v,c;
    cin >> n;
    e.resize(n);
    d.resize(n);
    for(int i=0; i<n; ++i) {
        cin >> u >> k;
        for(int j=0; j<k; ++j) {
            cin >> v >> c;
            e[u].push_back(Edge{c,v});
        }
        d[u]=INF;
    }

    d[0]=0;
    for(auto x : e[0]) {
        pq.push(x);
    }
    while(!pq.empty()) {
        etemp=pq.top(); pq.pop();
        v=etemp.second;
        c=etemp.first;
        if(d[v]<c) continue;
        d[v]=c;
        for(auto x : e[v]) {
            if(d[x.second]<=c+x.first) continue;
            pq.push(Edge{c+x.first,x.second});
        }
    }
    for(int i=0; i<n; ++i) {
        cout << i << " " << d[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
const int INF = 100000;
using namespace std;

int main(void){
  bool used[100];
  int n, G[100][100], p[100];
  cin >> n;
  for(int i=0; i < 100; i++){
    used[i] = false;
    for(int j=0; j < 100; j++){
      G[i][j] = INF;
    }
  }
  for(int i=0; i < n; i++){
    int vtmp, k;cin >> vtmp >> k;
    for(int j=0; j < k; j++){
      int v, c; cin >> v >> c;
      G[vtmp][v] = c;   
    }
  }

  int d[100];
  for(int i=0; i < n; i++){
    d[i] = INF;
  }
  d[0] = 0;

  for(int i=0; i < n; i++){
    int mind = INF;
    int minind;
    for(int j=0; j < n; j++){
      if(used[j] == false && d[j] < mind){
        mind = d[j]; minind = j;
      }
    }
    used[minind] = true;
    for(int j=0; j < n; j++){
      if(used[j] == false && G[minind][j] != INF){
        if(d[minind] + G[minind][j] < d[j]){
          d[j] = d[minind] + G[minind][j];
          p[j] = minind;
        }
      }
    }
  }
  for(int i=0; i < n; i++){
    cout << i << " " << d[i] << endl;
  }

  return 0;
}

C++: #include<iostream>
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];

void dijkstra() {
   int minv;
   int color[MAX], d[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) {
  	      	  minv = d[i];
  	      	  u = 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;
	int u, k, c, v;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][i] = INFTY;
		}
	}
	
	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<iostream>
#include<climits>
#include<vector>
using namespace std;

enum Color{WHITE, GRAY, BLACK};
struct edge{
        int v,c;
        edge(int v, int c): v(v), c(c){}
};

int n;
vector<vector<edge>> a;
int *r;

void shortestPath(){
        int tmpcost[n];
        Color color[n];
        for(int i=0;i<n;i++) tmpcost[i]=INT_MAX;
        for(int i=0;i<n;i++) color[i]=WHITE;
        tmpcost[0] = 0;
        color[0] = GRAY;
        while(1){
                int mincost=INT_MAX, argmin=-1;
                for(int i=0;i<n;i++){
                        if(color[i]!=GRAY) continue;
                        if(mincost>tmpcost[i]){
                                mincost = tmpcost[i];
                                argmin = i;
                        }
                }
                if(argmin==-1) break;
                color[argmin] = BLACK;
                r[argmin] = mincost;

                for(int i=0;i<a[argmin].size();i++){
                        edge e = a[argmin][i];
                        if(color[e.v]==BLACK) continue;
                        color[e.v] = GRAY;
                        tmpcost[e.v] = tmpcost[e.v]<(mincost+e.c)? tmpcost[e.v] : (mincost+e.c);
                }

        }

}
int main(){
        int u,k,v,c;
        cin>>n;
        a = vector<vector<edge>>(n);
        r = new int [n];
        for(int i=0;i<n;i++){
                cin>>u>>k;
                for(int j=0;j<k;j++){
                        cin>>v>>c;
                        a[u].emplace_back(edge(v,c));
                }
        }

        shortestPath();

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