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Commit 6c3753f

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solves Find K Closest Elements in java
1 parent f11d33d commit 6c3753f

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5 files changed

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‎README.md

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| 645 | [Set Mismatch](https://leetcode.com/problems/set-mismatch) | [![Java](assets/java.png)](src/SetMismatch.java) [![Python](assets/python.png)](python/set_mismatch.py) | |
382382
| 653 | [Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst) | [![Java](assets/java.png)](src/TwoSumIVInputIsABST.java) [![Python](assets/python.png)](python/two_sum_iv.py) | |
383383
| 657 | [Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin) | [![Java](assets/java.png)](src/RobotReturnToOrigin.java) [![Python](assets/python.png)](python/robot_return_to_origin.py) | |
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| 658 | [Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements) | [![Java](assets/java.png)](src/FindKClosestElements.java) | |
384385
| 661 | [Image Smoother](https://leetcode.com/problems/image-smoother) | [![Java](assets/java.png)](src/ImageSmoother.java) [![Python](assets/python.png)](python/image_smoother.py) | |
385386
| 665 | [Non Deceasing Array](https://leetcode.com/problems/non-decreasing-array) | [![Java](assets/java.png)](src/NonDecreasingArray.java) [![Python](assets/python.png)](python/non_decreasing_array.py) | |
386387
| 669 | [Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree) | [![Java](assets/java.png)](src/TrimABinarySearchTree.java) [![Python](assets/python.png)](python/trim_a_binary_search_tree.py) | |

‎src/FindKClosestElements.java

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// https://leetcode.com/problems/find-k-closest-elements
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// T: O(logN + KLogK)
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// S: O(logK)
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import java.util.ArrayList;
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import java.util.List;
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public class FindKClosestElements {
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public static List<Integer> findClosestElements(int[] array, int k, int x) {
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final int index = binarySearch(array, x);
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final List<Integer> result = new ArrayList<>();
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for (int left = index - 1, right = index ; k > 0 ; k--) {
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if (left == -1) {
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result.add(array[right++]);
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} else if (right == array.length) {
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result.add(array[left--]);
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} else {
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if (Math.abs(array[left] - x) <= Math.abs(array[right] - x)) {
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result.add(array[left--]);
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} else {
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result.add(array[right++]);
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}
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}
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}
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result.sort(Integer::compareTo);
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return result;
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}
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private static int binarySearch(int[] array, int x) {
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int left = 0, right = array.length - 1, middle;
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while (left <= right) {
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middle = left + (right - left) / 2;
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if (array[middle] == x) return middle;
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else if (array[middle] < x) left = middle + 1;
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else right = middle - 1;
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}
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return left;
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}
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public static void main(String[] args) {
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System.out.println(findClosestElements(new int[] {}, 3, 5));
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}
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}

‎src/FindMinimumInRotatedSortedArray.java

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// T: O(1)
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public class FindMinimumInRotatedSortedArray {
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public int findMin(int[] array) {
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if (!isRotated(array)) return array[0];
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for (int left = 0, right = array.length - 1 ; left <= right ; ) {
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int middle = left + (right - left) / 2;
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if (array[middle] > array[middle + 1]) return array[middle + 1];
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if (array[middle] < array[middle - 1]) return array[middle];
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if (array[middle] < array[array.length - 1]) right = middle - 1;
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else left = middle + 1;
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}
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return -1;
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public int findMin(int[] nums) {
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return nums[binarySearchPivotIndex(nums)];
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}
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private boolean isRotated(int[] array) {
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return array[0] > array[array.length - 1];
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private static int binarySearchPivotIndex(int[] array) {
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int left = 0, right = array.length - 1, middle;
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while (left <= right) {
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middle = left + (right - left) / 2;
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if (array[middle] > array[array.length - 1]) left = middle + 1;
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else right = middle - 1;
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}
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return left;
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}
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}

‎src/FindPeakElement.java

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// S: O(1)
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public class FindPeakElement {
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public static int findPeakElement(int[] array) {
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for (int left = 0, right = array.length - 1, middle ; left <= right ; ) {
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public int findPeakElement(int[] nums) {
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int left = 0, right = nums.length - 1, middle;
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while (left <= right) {
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middle = left + (right - left) / 2;
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if (isPeakElement(array, middle)) return middle;
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if (isOnIncreasingSlope(array, middle)) left = middle + 1;
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if (isPeak(nums, middle)) return middle;
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else if (middle + 1 < nums.length && nums[middle] < nums[middle + 1]) left = middle + 1;
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else right = middle - 1;
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}
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return -1;
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}
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private static boolean isOnIncreasingSlope(int[] array, int index) {
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return ((index > 0 && array[index - 1] < array[index]) || index == 0)
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&& ((index + 1 < array.length && array[index] < array[index + 1]) || index == array.length - 1);
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}
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private static boolean isPeakElement(int[] array, int index) {
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return ((index > 0 && array[index - 1] < array[index]) || index == 0)
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&& ((index + 1 < array.length && array[index + 1] < array[index]) || index == array.length - 1);
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private static boolean isPeak(int[] array, int x) {
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return (x - 1 < 0 || array[x - 1] < array[x])
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&& (x + 1 >= array.length || array[x] > array[x + 1]);
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}
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}

‎src/HelloWorld.java

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public class HelloWorld {
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public int search(int[] nums, int target) {
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final int pivotIndex = binarySearchPivotIndex(nums);
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final int answer = binarySearch(nums, 0, pivotIndex - 1, target);
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if (answer != -1) {
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return answer;
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public int[] searchRange(int[] nums, int target) {
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if (nums.length == 0) {
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return new int[] {-1, -1};
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}
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return binarySearch(nums, pivotIndex, nums.length - 1, target);
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return new int[] {
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leftBinarySearch(nums, target),
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rightBinarySearch(nums, target)
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};
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}
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private static int binarySearchPivotIndex(int[] array) {
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private static int leftBinarySearch(int[] array, intx) {
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int left = 0, right = array.length - 1, middle;
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while (left <= right) {
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middle = left + (right - left) / 2;
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if (array[middle] > array[array.length - 1]) left = middle + 1;
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if (array[middle] == x) {
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if (middle - 1 >= 0 && array[middle - 1] == x) {
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right = middle - 1;
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} else return middle;
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}
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else if (array[middle] < x) left = middle + 1;
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else right = middle - 1;
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}
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return left;
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return -1;
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}
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private static int binarySearch(int[] array, intstart, intend, int x) {
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int left = start, right = end, middle;
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private static int rightBinarySearch(int[] array, int x) {
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int left = 0, right = array.length - 1, middle;
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while (left <= right) {
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middle = left + (right - left) / 2;
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if (array[middle] == x) return middle;
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if (array[middle] == x) {
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if (middle + 1 < array.length && array[middle + 1] == x) {
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left = middle + 1;
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} else return middle;
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}
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else if (array[middle] < x) left = middle + 1;
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else right = middle - 1;
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}

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