Merge pull request neetcode-gh#2620 from aadil42/patch-63

javascript/0034-find-first-and-last-position-of-element-in-sorted-array.js

@@ -0,0 +1,47 @@
+/**
+ * Binary Search
+ * https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/
+ * Time O(log(n)) | Space O(1)
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+var searchRange = function(nums, target) {
+
+ const result = [];
+
+ result.push(binarySearch(true, nums, target));
+ result.push(binarySearch(false, nums, target));
+
+ return result;
+};
+
+var binarySearch = (isLeftBias, nums, target) => {
+ let left = 0;
+ let right = nums.length - 1;
+ let index = -1;
+
+ while(left <= right) {
+
+ const mid = (left + right) >> 1;
+
+ if(target > nums[mid]) {
+ left = mid+1;
+ }
+ if(target < nums[mid]) {
+ right = mid-1;
+ }
+
+ const isTarget = target === nums[mid];
+ if(isTarget) {
+ if(isLeftBias) {
+ index = mid;
+ right = mid - 1;
+ } else {
+ index = mid;
+ left = mid + 1;
+ }
+ }
+ }
+ return index;
+}