Beautiful Vertices

#1

What is the error in my code?
import java.util.Scanner;
import java.util.ArrayList;

class Main{

static class Edge{
    int p ;
    int v ;

    Edge(int p, int v){
        this.p = p; //parent
        this.v = v;
    }
}

public static void addEdge(ArrayList<ArrayList<Edge>>graph, int u, int v){
    graph.get(u).add(new Edge(u,v));
    // graph.get(v).add(new Edge(u));       
}

public static int countBVtx(ArrayList<ArrayList<Edge>> graph){

    int count = 0;

    for(int v = 1; v < graph.size(); v++){
        int pSize = graph.get(v).size();
        for(int i = 0; i<pSize; i++){
            Edge ce =graph.get(v).get(i);
            int cSize = graph.get(ce.v).size();
            if(cSize>pSize)
            {
                count++;
            }
        }
    }

    return count;        
}

public static void display(ArrayList<ArrayList<Edge>> graph){
    for(int i =1; i<graph.size(); i++){
        System.out.print(i+"->");
        for(int j =0; j<graph.get(i).size(); j++){
            Edge curr = graph.get(i).get(j);
            System.out.print("(" +curr.p+","+ curr.v + ")-");
        }
        System.out.println();
    }
}



public static Scanner scn = new Scanner(System.in);
public static void main(String[] args){
    ArrayList<ArrayList<Edge>> graph = new ArrayList<>();
    int n = scn.nextInt();      //no of vertex
    int m = scn.nextInt();      //no of edge

    for(int i = 0; i<=n; i++){
        graph.add(new ArrayList<Edge>());
    }

    for(int i = 0; i< m; i++){
        int a = scn.nextInt();
        int b = scn.nextInt();

        addEdge(graph,a,b);
    }
    // display(graph);
    System.out.print(countBVtx(graph));

}

}

#2

Anyone Please … there is a minute error which I am unable to find out

#3

It’s passing for sample test cases but while running it’s giving error for larger test cases. For eg. answer was 6535 and mine is 6531. So please help

#4

The compiler is giving this type of error:Note: Main.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details…However it is giving a warning in my editor also but the code is working. Please help:\

#5

Here is my code:import java.util.*; class Main{ public static int count = 0; public static Scanner scn = new Scanner(System.in); public static void main(String[] args){ int n = scn.nextInt(); int m = scn.nextInt(); ArrayList graph[] = new ArrayList[n+1]; for(int i = 0; i<=n;i++){ graph[i]= new ArrayList(); } for(int i = 0; i<m; i++){ int x = scn.nextInt(); int y = scn.nextInt(); graph[x].add(y); graph[y].add(x); } boolean [] vis = new boolean[n+1]; for(int i = 1; i<=n; i++){ if(!vis[i]){ dfs(graph,vis,i,-1); } } System.out.println(count); } public static void dfs(ArrayList graph[], boolean[] vis, int curr, int par){ vis[curr] = true; if(par!=-1){ int currChild = graph[curr].size(); int parChild = graph[par].size(); if(currChild>parChild) count++; } for(int i = 0; i<graph[curr].size(); i++){ if(!vis[graph[curr].get(i)]){ dfs(graph,vis,graph[curr].get(i),curr); } } } }

#6

Will anyone atleast reply? TA’s???

#7

Okay I will check for errors.

#8

I take that your latest code which you have provided is the one which is producing errors.

#9

Hi
You cannot create arrays of parameterized types. So your line 8 is wrong instead use an arraylist like :
ArrayList<ArrayList<Integer>> graph = new ArrayList<ArrayList<Integer>>(n+1);

also you have an error of par variable as in function call you have written it as pr
Finally, a tip, never use Scanner outside of a function in a static manner. This is the reason for your unsafe message you are receiving.