Problem:
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Single Source Shortest Path II

For a given weighted graph $G = (V, E)$, find the shortest path from a source to each vertex. For each vertex $u$, print the total weight of edges on the shortest path from vertex $0$ to $u$.

Input

In the first line, an integer $n$ denoting the number of vertices in $G$ is given. In the following $n$ lines, adjacency lists for each vertex $u$ are respectively given in the following format:

$u$ $k$ $v_1$ $c_1$ $v_2$ $c_2$ ... $v_k$ $c_k$

Vertices in $G$ are named with IDs $0, 1, ..., n-1$. $u$ is ID of the target vertex and $k$ denotes its degree. $v_i (i = 1, 2, ... k)$ denote IDs of vertices adjacent to $u$ and $c_i$ denotes the weight of a directed edge connecting $u$ and $v_i$ (from $u$ to $v_i$).

Output

For each vertex, print its ID and the distance separated by a space character in a line respectively. Print in order of vertex IDs.

Constraints

$1 \leq n \leq 10,000$

$0 \leq c_i \leq 100,000$

$|E| < 500,000$

All vertices are reachable from vertex $0$

Sample Input 1

5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3

Sample Output 1

0 0
1 2
2 2
3 1
4 3

Reference

Introduction to Algorithms, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. The MIT Press.

Solution in C++11 (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
vector<vector<P> > G;
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  G.resize(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;
      G[u].push_back(P(v,c));
    }
  }
  int d[n];
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;

  priority_queue<P,vector<P>,greater<P> > q;
  d[0]=0;
  q.push(P(0,0));

  while(!q.empty()){
    P p=q.top();q.pop();
    int u=p.second,c=p.first;
    //cout<<u<<" "<<c<<endl;
    if(d[u]<c) continue;
    for(P e:G[u]){
      int v=e.first,w=e.second;
      if(d[v]>d[u]+w){
	d[v]=d[u]+w;
	q.push(P(d[v],v));
	//cout<<v<<":"<<d[v]<<endl;
      }
    }
  }
  
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;
}