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<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;

#define INF 20000000
typedef struct Edge edge;

struct Edge{
  int src,dst,weight;
  Edge(int start,int end,int cost) :
	src(start),dst(end),weight(cost) {}
};

bool operator < (const edge &e,const edge &f){
  return (e.weight != f.weight) ? (e.weight > f.weight) : (e.src != f.src) ? (e.src < f.src) : (e.dst < f.dst);
}

typedef vector<edge> Edges;

vector<int> dijkstra(Edges,int);

int main(int argc,char* argv[]){
  int n,v,k,dst,weight;
  Edges es;
  vector<int> vec;

  cin >> n;
  for(int i = 0;i < n;i++){
	cin>> v >> k;
	vec.push_back(v);
	for(int j = 0;j < k;j++){
	  cin >> dst >> weight;
	  edge e(i,dst,weight);
	  es.push_back(e);
	}
  }

  vector<int> dist = dijkstra(es,n);

  for(int i = 0;i < n;i++)
	printf("%d %d\n",vec[i],dist[i]);
  return 0;
}

vector<int> dijkstra(Edges es,int n){
  vector<int> dist(n);
  priority_queue<edge> que;
  Edges l[n];
  dist.assign(n,INF);
  dist[0] = 0;

  for(int i = 0;i < (int)es.size();i++){
	edge e = es[i];
	l[e.src].push_back(e);
  }

  for(int i = 0;i < (int)l[0].size();i++)
	que.push(l[0][i]);

  while(!que.empty()){
	edge e = que.top();
	que.pop();
	if(dist[e.dst] > dist[e.src] + e.weight){
	  dist[e.dst] = dist[e.src] + e.weight;

	  for(int i = 0;i < (int)l[e.dst].size();i++)
		que.push(l[e.dst][i]);
	}
  }

  return dist;
}

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 min;
   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 ) {
      min = INFTY; 
      int a = -1;
      for ( int i = 0; i < n; i++ ) {
         if ( min > d[i] && color[i] != BLACK ) {
             a = i;
             min = d[i];
         }
      }

      if ( a == -1 ) break;
      color[a] = BLACK;
      
      for ( int v = 0; v < n; v++ ) {
         if ( color[v] != BLACK && M[a][v] != INFTY ) {
            if ( d[v] > d[a] + M[a][v] ) {
               d[v] = d[a] + M[a][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 < n; j++ ) {
      cin >> v >> c;
      M[u][v] = c;
      }
   }

   dijkstra();

   return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <climits>
#include <cstring>

using namespace std;

#define SWAP(type, a, b) do { type t = a; a = b; b = t; } while(0)

typedef struct {
    int* verIdx;
    int num;
} Heap;

int* d; 
int* weight;
int n;

void makeMinHeap(Heap *heap, int idx);
void insert(Heap *heap, int key);
int extract(Heap *heap);

static inline int getParent(int idx) { return idx / 2; }
static inline int getLeft(int idx) { return idx * 2; }
static inline int getRight(int idx) { return idx * 2 + 1; }
static inline bool isCorrectHeapIdx(int idx, int heapSize) { return idx <= heapSize && 1 <= idx; }
static inline bool isEmpty(Heap *heap) { return heap->num <= 0; }

static inline int getMinCost(int idx) {
    return d[idx];
}

void makeMinHeap(Heap *heap, int idx) {
    int left = getLeft(idx);
    int right = getRight(idx);

    int minIdx = idx;
    if(isCorrectHeapIdx(left, heap->num) && getMinCost(heap->verIdx[minIdx]) > getMinCost(heap->verIdx[left])) {
        minIdx = left;
    } if(isCorrectHeapIdx(right, heap->num) && getMinCost(heap->verIdx[minIdx]) > getMinCost(heap->verIdx[right])) {
        minIdx = right;
    }

    if(minIdx != idx) {
        SWAP(int, heap->verIdx[minIdx], heap->verIdx[idx]);
        makeMinHeap(heap, minIdx);
    }
}

void insert(Heap *heap, int* key) {
    heap->verIdx[++heap->num] = *key;
    for(int i = getParent(heap->num); i >= 1; i = getParent(i)) {
        makeMinHeap(heap, i);
    }
}

void extract(Heap *heap, int* key) {
    *key = heap->verIdx[1];
    heap->verIdx[1] = heap->verIdx[heap->num--];
    makeMinHeap(heap, 1);
}

static inline bool isConnected(int s, int t) {
    return weight[s * n + t] != INT_MAX;
}

static inline int getWeight(int s, int t) {
    return weight[s * n + t];
}

void solve(int s) {
    Heap que;
    bool* isAddS = new bool[n]();

    que.verIdx = new int[n * n];
    que.num = 0;

    d = new int[n];
    d[s] = 0;
    for(int i = 0; i < n; i++) {
        if(s != i) {
            d[i] = INT_MAX;
        }
    }
    
    insert(&que, &s);

    while(1) {
        int u;
        while(1) {
            if(isEmpty(&que)) {
                return;
            } 

            extract(&que, &u);
            if(!isAddS[u]) {
                break;
            }
        }

        isAddS[u] = true;

        for(int i = 0; i < n; i++) {
            if(isConnected(u, i) && !isAddS[i]) {
                if(d[u] + getWeight(u, i) < d[i]) {
                    d[i] = d[u] + getWeight(u, i);
                }
                insert(&que, &i);
            }
        }
    }

    return;
}

int main() {

    scanf("%d", &n);

    weight = new int[n * n];

    for(int i = 0; i < n * n; i++) {
        weight[i] = INT_MAX;
    }
    

    for(int i = 0; i < n; i++) {
        int s;
        int deg;

        scanf("%d %d", &s, &deg);
        for(int j = 0; j < deg; j++) {
            int t;
            int w;

            scanf("%d %d", &t, &w);

            weight[s * n + t] = w;
        }
    }

    solve(0);

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