solves kth missing positive number

Author: anishLearnsToCode

README.md

@@ -387,5 +387,5 @@
 | 1523 | [Count Odd Numbers In Interval Range](https://leetcode.com/problems/count-odd-numbers-in-an-interval-range)                                          |                                                         [![Java](assets/java.png)](src/CountOddNumbersInIntervalRange.java)                                                          |                                                                                                                                   |
 | 1528 | [Shuffle Strings](https://leetcode.com/problems/shuffle-string)                                                                                      |                                                                  [![Java](assets/java.png)](src/ShuffleString.java)                                                                  |                                                                                                                                   |
 | 1534 | [Count Good Triplets](https://leetcode.com/problems/count-good-triplets)                                                                             |                                                                [![Java](assets/java.png)](src/CountGoodTriplets.java)                                                                |                                                                                                                                   |
-| 1539 | [Kth Missing Positive Number](https://leetcode.com/problems/kth-missing-positive-number)                                                             |                                                                                                                                                                                      |                                                                                                                                   |
+| 1539 | [Kth Missing Positive Number](https://leetcode.com/problems/kth-missing-positive-number)                                                             |                                                            [![Java](assets/java.png)](src/KthMissingPositiveNumber.java)                                                             |                                                                                                                                   |
 | 1544 | [Make The String Great](https://leetcode.com/problems/make-the-string-great)                                                                         |                                                                                                                                                                                      |                                                                                                                                   |

src/KthMissingPositiveNumber.java

@@ -0,0 +1,19 @@
+// https://leetcode.com/problems/kth-missing-positive-number
+// T: O(n)
+// S: O(1)
+
+public class KthMissingPositiveNumber {
+    public int findKthPositive(int[] arr, int k) {
+        int pointer = 1, missing = 0;
+        for (int index = 0, current = arr[index]; missing < k ; ) {
+            if (pointer < current) {
+                missing++;
+            } else {
+                index++;
+                current = index == arr.length ? Integer.MAX_VALUE : arr[index];
+            }
+            pointer++;
+        }
+        return pointer - 1;
+    }
+}