Https://cses.fi/problemset/task/1195

Problems and Contests
#1

https://cses.fi/problemset/task/1195

Here is my code :-1:

// Online C++ compiler to run C++ program online
#include <climits>
#include <iostream>
#include<bits/stdc++.h>
using namespace std;
/*
10 12
1 2 4
5 7 1
4 6 4
7 9 3
9 10 1
7 8 5
1 3 1
6 7 4
4 5 1
3 4 2
8 10 5
2 4 3
*/

void print(vector<long long>&arr){
    cout<<"array size is " << arr.size();
    for(int i=0;i<arr.size();i++){
        cout<<i<<" value is "<<arr[i]<<" ";
    }
    return;
}
void djikstra(vector<vector<pair<int,int>>>&graph,vector<long long>&dist,int src){
    
    int n=graph.size()-1;
    using T =pair<long long,int>;
    priority_queue<T , vector<T> ,greater<T>>pq;
    vector<bool>vis(n+1,false);
    pq.push({0ll+0,src});
    vis[src]=true;
    dist[src]=0ll+0;
    
    while(pq.size()>0){
         pair<long long,int>front=pq.top();
         pq.pop();
         
         int node=front.second;
   //      cout<<"Node comes "<<node<<" ";
         long long currDis=front.first;
         
         for(pair<int,int>nbr:graph[node]){
             if(vis[nbr.second]==false){
             //   cout<<" nbr node "<<nbr.second <<" is unvisited  updating ist distance";
                 vis[nbr.second]=true;
                 dist[nbr.second]=0ll+currDis+nbr.first;
                 pq.push({currDis+nbr.first,nbr.second});
               //  cout<<pq.size();
             }else{
                 if(dist[nbr.second]>currDis+nbr.first){
                 //    cout<<" minimising  the distance of "<<nbr.second ;
                     dist[nbr.second]=currDis+nbr.first;
                 }
             }
         }
        // cout<<
         
        
        
        
    
    }
     return;   
}
void findOptimalCost(vector<vector<pair<int,int>>>&graph,vector<long long>&dist1,vector<long long>&dist2){
    
    int n = graph.size()-1;
    long long minCost=LLONG_MAX;
    pair<int,int>path;
    for(int a=1;a<=n;a++){
        // if not reachable continue  to next vertex
        if(dist1[a]==LLONG_MAX)continue;
        //reachable try to half each edge of v
        for(pair<int,int>nbr:graph[a]){
            int b=nbr.second,cost=nbr.first;
            if(dist2[b]==LLONG_MAX)continue;
            //now 1-->A A-->B B-->N all reachabel now half the cost and update the minCost
            long long  d1=dist1[a],d2=dist2[b],halved=cost/2;
            if( d1+halved+ d2 <minCost ){
             //   cout<<"Chnaging on a= "<<a<<" - b ="<<b<<" "<<endl;
                minCost=d1+halved+d2;
                path={a,b};
            }
        }
    }
    
    cout<<minCost;
    //<<path.first<<" "<<path.second;

    
    
    
    
}
void solve(){
   
    // int n,m;cin>>n>>m;
    //  cout<<"s1"; int n=3,m=4;

    int n,m;cin>>n>>m;
    vector<long long>dist1(n+1,LLONG_MAX),dist2(n+1,LLONG_MAX);
  //  cout<<"n m done";
    vector<vector<pair<int,int>>>graph(n+1,vector<pair<int,int>>()),rev_graph(n+1,vector<pair<int,int>>());
    for(int i=0;i<m;i++){
        int u,v,cost;
        cin>>u>>v>>cost;
     //   cout<<"taking input";
        graph[u].push_back({cost,v});
        rev_graph[v].push_back({cost,u});
    }
  //  cout<<"done input";
    djikstra(graph,dist1,1);
 //   print(dist1);
  //  cout<<endl;
    djikstra(rev_graph,dist2,n);
    
  //   print(dist2);
    // cout<<endl;
    findOptimalCost(graph,dist1,dist2);
    
    
}
int main() {
    // Write C++ code here
     
    solve();
    

    return 0;
}

Not all testcases getting passed where i am behin din this code ??