Add solution #1649

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,448 LeetCode solutions in JavaScript
+# 1,449 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
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 1646|[Get Maximum in Generated Array](./solutions/1646-get-maximum-in-generated-array.js)|Easy|
 1647|[Minimum Deletions to Make Character Frequencies Unique](./solutions/1647-minimum-deletions-to-make-character-frequencies-unique.js)|Medium|
 1648|[Sell Diminishing-Valued Colored Balls](./solutions/1648-sell-diminishing-valued-colored-balls.js)|Medium|
+1649|[Create Sorted Array through Instructions](./solutions/1649-create-sorted-array-through-instructions.js)|Hard|
 1657|[Determine if Two Strings Are Close](./solutions/1657-determine-if-two-strings-are-close.js)|Medium|
 1668|[Maximum Repeating Substring](./solutions/1668-maximum-repeating-substring.js)|Easy|
 1669|[Merge In Between Linked Lists](./solutions/1669-merge-in-between-linked-lists.js)|Medium|

solutions/1649-create-sorted-array-through-instructions.js

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+/**
+ * 1649. Create Sorted Array through Instructions
+ * https://leetcode.com/problems/create-sorted-array-through-instructions/
+ * Difficulty: Hard
+ *
+ * Given an integer array instructions, you are asked to create a sorted array from the elements in
+ * instructions. You start with an empty container nums. For each element from left to right in
+ * instructions, insert it into nums. The cost of each insertion is the minimum of the following:
+ * - The number of elements currently in nums that are strictly less than instructions[i].
+ * - The number of elements currently in nums that are strictly greater than instructions[i].
+ *
+ * For example, if inserting element 3 into nums = [1,2,3,5], the cost of insertion is min(2, 1)
+ * (elements 1 and 2 are less than 3, element 5 is greater than 3) and nums will become [1,2,3,3,5].
+ *
+ * Return the total cost to insert all elements from instructions into nums. Since the answer may
+ * be large, return it modulo 109 + 7
+ */
+
+/**
+ * @param {number[]} instructions
+ * @return {number}
+ */
+var createSortedArray = function(instructions) {
+  const MOD = 1e9 + 7;
+  const maxValue = Math.max(...instructions);
+  const fenwickTree = new Array(maxValue + 1).fill(0);
+  let totalCost = 0;
+
+  for (let i = 0; i < instructions.length; i++) {
+    const value = instructions[i];
+    const lessCount = query(value - 1);
+    const greaterCount = i - query(value);
+    totalCost = (totalCost + Math.min(lessCount, greaterCount)) % MOD;
+    update(value);
+  }
+
+  return totalCost;
+
+  function update(index) {
+    for (let i = index; i <= maxValue; i += i & -i) {
+      fenwickTree[i]++;
+    }
+  }
+
+  function query(index) {
+    let sum = 0;
+    for (let i = index; i > 0; i -= i & -i) {
+      sum += fenwickTree[i];
+    }
+    return sum;
+  }
+};