MaxConsecutiveOnesCircularArray.java

// Function to return the count of maximum 
// consecutive 1's in a binary circular array 
public static int getMaxLength(int arr[]) {
   int n = arr.length;

   // Starting index
   int start = 0;
   //it will contain number of ones from left
   //to right till we encounter zero.
   int onesFromStart = 0;
   while (start < n && arr[start] == 1) {
      onesFromStart++;
      start++;
   }

   // Ending index
   int end = n - 1;
   //it will contain number of ones from right
   //to left till we encounter zero.
   int onesFromEnd = 0;
   while (end >= 0 && arr[end] == 1) {
      onesFromEnd++;
      end--;
   }
   // The array contains all 1s
   if (start > end)
      return n;

   //number of ones between start and end
   int onesInMid = 0;
   int result = 0;

   for (int i = start; i <= end; i++) {
      if (arr[i] == 1) {
         onesInMid++;
         result = Math.max(result, onesInMid);
      } else
         onesInMid = 0;
      }
   return Math.max(result, onesFromStart + onesFromEnd);
}