Create CelebrityProblem

Author: harshithasudhakar

Stacks/Problems/CelebrityProblem

@@ -0,0 +1,44 @@
+import java.util.*;
+
+class CelebrityProblem{
+
+    static int isCelebrity(int[][] mat, int n){
+
+        Stack<Integer> stk = new Stack<>();
+
+        for(int i = 0; i<n; i++){
+            stk.push(i);
+        }
+
+        while(stk.size()>1){
+            int a = stk.pop();
+            int b = stk.pop();
+            if(mat[a][b]==1){
+               stk.push(b);
+            }
+            else{
+                stk.push(a);
+            }
+        }
+        int candidate = stk.pop();
+        for(int i = 0; i<n; i++){
+            if(i!=candidate && (mat[candidate][i] == 1 || mat[i][candidate] == 0)){
+                return -1;
+            }
+        }
+        
+        return candidate;
+    }
+
+    public static void main(String[] args){
+        Scanner input = new Scanner(System.in);
+        int n = input.nextInt();
+        int[][] mat = new int[n][n];
+        for(int i = 0; i<n; i++){
+            for(int j = 0; j<n; j++){
+                mat[i][j] = input.nextInt();
+            }
+        }
+        System.out.println(isCelebrity(mat, n));
+    }
+}