Package g0801_0900.s0900_rle_iterator

Class RLEIterator

java.lang.Object
g0801_0900.s0900_rle_iterator.RLEIterator
public class RLEIterator extends Object
900 - RLE Iterator\. Medium We can use run-length encoding (i.e., **RLE** ) to encode a sequence of integers. In a run-length encoded array of even length `encoding` ( **0-indexed** ), for all even `i`, `encoding[i]` tells us the number of times that the non-negative integer value `encoding[i + 1]` is repeated in the sequence. * For example, the sequence `arr = [8,8,8,5,5]` can be encoded to be `encoding = [3,8,2,5]`. `encoding = [3,8,0,9,2,5]` and `encoding = [2,8,1,8,2,5]` are also valid **RLE** of `arr`. Given a run-length encoded array, design an iterator that iterates through it. Implement the `RLEIterator` class: * `RLEIterator(int[] encoded)` Initializes the object with the encoded array `encoded`. * `int next(int n)` Exhausts the next `n` elements and returns the last element exhausted in this way. If there is no element left to exhaust, return `-1` instead. **Example 1:** **Input** ["RLEIterator", "next", "next", "next", "next"] [[[3, 8, 0, 9, 2, 5]], [2], [1], [1], [2]] **Output:** [null, 8, 8, 5, -1] **Explanation:** RLEIterator rLEIterator = new RLEIterator([3, 8, 0, 9, 2, 5]); // This maps to the sequence [8,8,8,5,5]. rLEIterator.next(2); // exhausts 2 terms of the sequence, returning 8. The remaining sequence is now [8, 5, 5]. rLEIterator.next(1); // exhausts 1 term of the sequence, returning 8. The remaining sequence is now [5, 5]. rLEIterator.next(1); // exhausts 1 term of the sequence, returning 5. The remaining sequence is now [5]. rLEIterator.next(2); // exhausts 2 terms, returning -1. This is because the first term exhausted was 5, // but the second term did not exist. Since the last term exhausted does not exist, we return -1. **Constraints:** * `2 <= encoding.length <= 1000` * `encoding.length` is even. * 0 <= encoding[i] <= 109 * 1 <= n <= 109 * At most `1000` calls will be made to `next`.

  • Constructor Details

    • RLEIterator

      public RLEIterator(int[] encoding)

  • Method Details

    • next

      public int next(int n)