Package g1201_1300.s1286_iterator_for_combination

Class CombinationIterator

java.lang.Object
g1201_1300.s1286_iterator_for_combination.CombinationIterator
public class CombinationIterator extends Object
1286 - Iterator for Combination\. Medium Design the `CombinationIterator` class: * `CombinationIterator(string characters, int combinationLength)` Initializes the object with a string `characters` of **sorted distinct** lowercase English letters and a number `combinationLength` as arguments. * `next()` Returns the next combination of length `combinationLength` in **lexicographical order**. * `hasNext()` Returns `true` if and only if there exists a next combination. **Example 1:** **Input** ["CombinationIterator", "next", "hasNext", "next", "hasNext", "next", "hasNext"] [["abc", 2], [], [], [], [], [], []] **Output:** [null, "ab", true, "ac", true, "bc", false] **Explanation:** CombinationIterator itr = new CombinationIterator("abc", 2); itr.next(); // return "ab" itr.hasNext(); // return True itr.next(); // return "ac" itr.hasNext(); // return True itr.next(); // return "bc" itr.hasNext(); // return False **Constraints:** * `1 <= combinationLength <= characters.length <= 15` * All the characters of `characters` are **unique**. * At most 104 calls will be made to `next` and `hasNext`. * It is guaranteed that all calls of the function `next` are valid.

  • Constructor Details

    • CombinationIterator

      public CombinationIterator(String characters, int combinationLength)

  • Method Details

    • next

      public String next()

    • hasNext

      public boolean hasNext()