877.Stone Game === ###### tags: `Medium`,`Array`,`Math`,`DP` [877. Stone Game](https://leetcode.com/problems/stone-game/) ### 題目描述 Alice and Bob play a game with piles of stones. There are an `even` number of piles arranged in a row, and each pile has a **positive** integer number of stones `piles[i]`. The objective of the game is to end with the most stones. The **total** number of stones across all the piles is **odd**, so there are no ties. Alice and Bob take turns, with **Alice starting first**. Each turn, a player takes the entire pile of stones either from the **beginning** or from the **end** of the row. This continues until there are no more piles left, at which point the person with the **most stones wins**. Assuming Alice and Bob play optimally, return `true` *if Alice wins the game, or* `false` *if Bob wins.* ### 範例 **Example 1:** ``` Input: piles = [5,3,4,5] Output: true Explanation: Alice starts first, and can only take the first 5 or the last 5. Say she takes the first 5, so that the row becomes [3, 4, 5]. If Bob takes 3, then the board is [4, 5], and Alice takes 5 to win with 10 points. If Bob takes the last 5, then the board is [3, 4], and Alice takes 4 to win with 9 points. This demonstrated that taking the first 5 was a winning move for Alice, so we return true. ``` **Example 2:** ``` Input: piles = [3,7,2,3] Output: true ``` **Constraints**: * 2 <= `piles.length` <= 500 * `piles.length` is **even**. * 1 <= `piles[i]` <= 500 * `sum(piles[i])` is **odd**. ### 解答 ### Reference [回到題目列表](https://hackmd.io/@Marsgoat/leetcode_every_day)