Write an iterator that iterates through a run-length encoded sequence.
The iterator is initialized by RLEIterator(int[] A)
, where A
is a run-length encoding of some sequence. More specifically, for all even i
, A[i]
tells us the number of times that the non-negative integer value A[i+1]
is repeated in the sequence.
The iterator supports one function: next(int n)
, which exhausts the next n
elements (n >= 1
) and returns the last element exhausted in this way. If there is no element left to exhaust, next
returns -1
instead.
For example, we start with A = [3,8,0,9,2,5]
, which is a run-length encoding of the sequence [8,8,8,5,5]
. This is because the sequence can be read as "three eights, zero nines, two fives".
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 is initialized with RLEIterator([3,8,0,9,2,5]). This maps to the sequence [8,8,8,5,5]. RLEIterator.next is then called 4 times: .next(2) exhausts 2 terms of the sequence, returning 8. The remaining sequence is now [8, 5, 5]. .next(1) exhausts 1 term of the sequence, returning 8. The remaining sequence is now [5, 5]. .next(1) exhausts 1 term of the sequence, returning 5. The remaining sequence is now [5]. .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.
Note:
<li><code>0 <= A.length <= 1000</code></li>
<li><code>A.length</code> is an even integer.</li>
<li><code>0 <= A[i] <= 10^9</code></li>
<li>There are at most <code>1000</code> calls to <code>RLEIterator.next(int n)</code> per test case.</li>
<li>Each call to <code>RLEIterator.next(int n)</code> will have <code>1 <= n <= 10^9</code>.</li>