Added famous book allocation problem

Book_Allocation.java

@@ -0,0 +1,84 @@
+//Problem : https://www.geeksforgeeks.org/allocate-minimum-number-pages/
+
+// Java program for optimal allocation of pages
+
+public class Book_Allocation {
+	// Utility method to check if current minimum value
+	// is feasible or not.
+	static boolean isPossible(int arr[], int n, int m,
+							int curr_min)
+	{
+		int studentsRequired = 1;
+		int curr_sum = 0;
+
+		// iterate over all books
+		for (int i = 0; i < n; i++) {
+			curr_sum += arr[i];
+			if (curr_sum > curr_min) {
+				studentsRequired++; // increment student
+									// count
+
+				curr_sum = arr[i]; // update curr_sum
+			}
+		}
+
+		return studentsRequired <= m;
+	}
+
+	// method to find minimum pages
+	static int findPages(int arr[], int n, int m)
+	{
+		int sum = 0;
+
+		// return -1 if no. of books is less than
+		// no. of students
+		if (n < m)
+			return -1;
+
+		// Count total number of pages
+		for (int i = 0; i < n; i++)
+			sum += arr[i];
+
+		// initialize start as arr[n-1] pages(minimum answer
+		// possible) and end as total pages(maximum answer
+		// possible)
+		int start = arr[n - 1], end = sum;
+		int result = Integer.MAX_VALUE;
+
+		// traverse until start <= end
+		while (start <= end) {
+			// check if it is possible to distribute
+			// books by using mid is current minimum
+			int mid = start + (end - start) / 2;
+			if (isPossible(arr, n, m, mid)) {
+				// update result to current distribution
+				// as it's the best we have found till now.
+				result = mid;
+
+				// as we are finding minimum so,
+				end = mid - 1;
+			}
+
+			else
+				// if not possible, means pages should be
+				// increased ,so update start = mid + 1
+				start = mid + 1;
+		}
+
+		// at-last return minimum no. of pages
+		return result;
+	}
+
+	// Driver Method
+	public static void main(String[] args)
+	{
+
+		int arr[] = { 12, 34, 67,
+					90 }; // Number of pages in books
+
+		int m = 2; // No. of students
+
+		System.out.println("Minimum number of pages = "
+						+ findPages(arr, arr.length, m));
+	}
+}