Add solution #1690

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,477 LeetCode solutions in JavaScript
+# 1,478 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1302,6 +1302,7 @@
 1687|[Delivering Boxes from Storage to Ports](./solutions/1687-delivering-boxes-from-storage-to-ports.js)|Hard|
 1688|[Count of Matches in Tournament](./solutions/1688-count-of-matches-in-tournament.js)|Easy|
 1689|[Partitioning Into Minimum Number Of Deci-Binary Numbers](./solutions/1689-partitioning-into-minimum-number-of-deci-binary-numbers.js)|Medium|
+1690|[Stone Game VII](./solutions/1690-stone-game-vii.js)|Medium|
 1716|[Calculate Money in Leetcode Bank](./solutions/1716-calculate-money-in-leetcode-bank.js)|Easy|
 1718|[Construct the Lexicographically Largest Valid Sequence](./solutions/1718-construct-the-lexicographically-largest-valid-sequence.js)|Medium|
 1726|[Tuple with Same Product](./solutions/1726-tuple-with-same-product.js)|Medium|

solutions/1690-stone-game-vii.js

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+/**
+ * 1690. Stone Game VII
+ * https://leetcode.com/problems/stone-game-vii/
+ * Difficulty: Medium
+ *
+ * Alice and Bob take turns playing a game, with Alice starting first.
+ *
+ * There are n stones arranged in a row. On each player's turn, they can remove either the leftmost
+ * stone or the rightmost stone from the row and receive points equal to the sum of the remaining
+ * stones' values in the row. The winner is the one with the higher score when there are no stones
+ * left to remove.
+ *
+ * Bob found that he will always lose this game (poor Bob, he always loses), so he decided to
+ * minimize the score's difference. Alice's goal is to maximize the difference in the score.
+ *
+ * Given an array of integers stones where stones[i] represents the value of the ith stone from
+ * the left, return the difference in Alice and Bob's score if they both play optimally.
+ */
+
+/**
+ * @param {number[]} stones
+ * @return {number}
+ */
+var stoneGameVII = function(stones) {
+  const n = stones.length;
+  const prefixSum = new Array(n + 1).fill(0);
+  const dp = new Array(n).fill().map(() => new Array(n).fill(0));
+
+  for (let i = 0; i < n; i++) {
+    prefixSum[i + 1] = prefixSum[i] + stones[i];
+  }
+
+  for (let len = 2; len <= n; len++) {
+    for (let start = 0; start <= n - len; start++) {
+      const end = start + len - 1;
+      const leftScore = prefixSum[end + 1] - prefixSum[start + 1] - dp[start + 1][end];
+      const rightScore = prefixSum[end] - prefixSum[start] - dp[start][end - 1];
+      dp[start][end] = Math.max(leftScore, rightScore);
+    }
+  }
+
+  return dp[0][n - 1];
+};