networkdelay.cpp

class Solution {
public:
    int networkDelayTime(vector<vector<int>>& times, int N, int K) {
        const int E=times.size();
        int time=-1;
        vector<pair<int,int>> adj[N+1]; 
        for(int i=0;i<E;i++){
            adj[times[i][0]].push_back(make_pair(times[i][1],times[i][2]));
        }
        vector<int> d(N+1,1<<30);
        priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> pq;
        pq.push(make_pair(0,K));
        d[K]=0;
        while(!pq.empty()){
            int u=pq.top().second;
            int dorikindidonga=pq.top().first;
            pq.pop();
            if(d[u]>=dorikindidonga){
                time=max(dorikindidonga,time);
                for(auto x:adj[u]){
                    int v=x.first;
                    int weight=x.second;
                    if(d[v]>d[u]+weight){
                        d[v]=d[u]+weight;
                        pq.push(make_pair(d[v],v));
                    }    
                } 
            }
        }
        for(int i=1;i<=N;i++){
            if(d[i]==1<<30){
                return -1;
            }
        }
         return time;
    }
};