Binary Search 02 Completed

find_first_and_last_position_array_test.js

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+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+var searchRange = function (nums, target) {
+  let firstIndex = binarySearch(nums, 0, nums.length - 1, target, -1);
+  if (firstIndex == -1) {
+    return [-1, -1];
+  }
+  let lastIndex = binarySearch(nums, firstIndex, nums.length - 1, target, 1);
+  return [firstIndex, lastIndex];
+};
+
+var binarySearch = function (nums, left, right, target, direction) {
+  while (left <= right) {
+    let mid = Math.round(left + (right - left) / 2);
+    if (nums[mid] == target) {
+      let nextIndex = mid + direction;
+      if (nextIndex >= 0 && nextIndex <= right && nums[nextIndex] == target) {
+        if (nextIndex > mid) {
+          left = nextIndex;
+        } else if (nextIndex < mid) {
+          right = nextIndex;
+        } else {
+          return mid;
+        }
+      } else {
+        return mid;
+      }
+    } else if (nums[mid] > target) {
+      right = mid - 1;
+    } else {
+      left = mid + 1;
+    }
+  }
+  return -1;
+};
+
+test("Scenario #1: [5, 7, 7, 8, 8, 10]", () => {
+  let result = searchRange([5, 7, 7, 8, 8, 10], 8);
+  let expected = [3, 4];
+  expect(result).toStrictEqual(expected);
+});
+test("Scenario #2: [3, 3, 3]", () => {
+  expect(searchRange([3, 3, 3], 3)).toStrictEqual([0, 2]);
+});

find_minimum_in_rotated_array_test.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var findMin = function (nums) {
+  let left = 0;
+  let right = nums.length - 1;
+
+  while (left < right) {
+    let mid = Math.round(left + (right - left) / 2);
+    let element = nums[mid];
+    // If left half is sorted the move search range to right side
+    // else left side.
+
+    if (element < nums[right]) {
+      // Move Left
+      right = mid;
+    } else {
+      left = mid;
+    }
+  }
+  return left;
+};
+
+test("Scenario #1: [5,6,7,1,2,3,4]", () => {
+  expect(findMin([5, 6, 7, 1, 2, 3, 4])).toStrictEqual(3);
+});
+test("Scenario #2: [3, 1, 2]", () => {
+  expect(findMin([3, 1, 2])).toStrictEqual(1);
+});
+test("Scenario #3: [1, 2, 3]", () => {
+  expect(findMin([1, 2, 3])).toStrictEqual(123);
+});