Graph-Bellman-Ford algorithm

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

int main()
{
    int n,m;
    int u,v,w;
    cin>>n>>m;
    pair<int,int>p;
    vector<pair<int,int>>temp;
    //input format
    // 4 4  <-n,m
    // 0 1 4  <-u,v,w
    // 0 3 5
    // 3 2 3 
    // 2 1 -10
    // 0   <-s
    
    vector<vector<pair<int,int>>>a(n,temp);
    //n # of vertices  m # of edges
    for(int i=0;i<m;i++)
    {
        cin>>u>>v>>w;
        p=make_pair(v,w);
        a[u].push_back(p);
    }
    int s;//source
    cin>>s;
    int distance[n];
    distance[s]=0;
    for(int i=1;i<n;i++)
    {
        distance[i]=INT_MAX;
    }
    
    
    //Bellman ford algorithm
    for(int i=0;i<n-1;i++)
    {
        for(int j=0;j<a.size();j++)
        {
            for(int k=0;k<a[j].size();k++)
            {
                u=j;
                p=a[u][k];
                v=p.first;
                w=p.second;
                if(distance[u]+w<distance[v])
                {
                    distance[v]=distance[u]+w;
                }
            }
        }
        
    }
    
    cout<<"Path length of each vertices are::";
    for(int i=0;i<n;i++)
    {
        cout<<"\n"<<i<<"   "<<distance[i];
    }
    
}