Challenge: Solve a Celebrity Problem Using a Stack

Problem Statement #

In this problem, you have to implement findCelebrity() method to find the celebrity in a party (matrix) using a stack. A celebrity is someone that everyone knows, but he/she doesn’t know anyone at the party.

Method Prototype: #

int findCelebrity(int[][] party,int numPeople);

Where the party is a reference variable storing a 2D matrix, which has stored all the information about acquaintances, numPeople and the number of people present in the party.

In the party matrix, a particular [row][col] stores acquaintance information for row and col. In other words, if [row][col] == 1, then it means row knows col, and if it’s zero, then it means row doesn’t know col. Remember that everyone knows a celebrity, but the celebrity doesn’t know the people at the party.

An illustration is also provided for your understanding.

Output: #

It will return - 1 if there is no celebrity in the party. Otherwise, it will return the ID or number of celebrities from the party matrix.

Sample Input #

party = {
          {0,1,1,0},
          {1,0,1,1},
       	  {0,0,0,0},
      	  {0,1,1,0},
				}

numPeople = 4 (Number of rows in party array)      

Sample Output #

2 (because row Index = 2 is a celebrity)