Codeforces Global Round 1 D. Jongmah

最新推荐文章于 2022-02-26 21:13:17 发布

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最新推荐文章于 2022-02-26 21:13:17 发布

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给定手中有 n 个不同数值的瓷砖，目标是形成尽可能多的合法三连组合（数值相同或连续）。题目要求找出能够形成的最多三连组合数量。解答需要考虑数值为 x 的瓷砖可以组成 {x-1,x,x+1} 或 {x,x,x} 的组合，并通过动态规划方法解决当瓷砖个数小于等于 2 时的情况。" 113729481,1266039,IDEA Maven编译错误：PKIX path building failed解决方案,"['intellij idea', 'maven', '错误修复']

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You are playing a game of Jongmah. You don't need to know the rules to solve this problem. You have nntiles in your hand. Each tile has an integer between 11 and mm written on it.

To win the game, you will need to form some number of triples. Each triple consists of three tiles, such that the numbers written on the tiles are either all the same or consecutive. For example, 7,7,77,7,7 is a valid triple, and so is 12,13,1412,13,14, but 2,2,32,2,3 or 2,4,62,4,6 are not. You can only use the tiles in your hand to form triples. Each tile can be used in at most one triple.

To determine how close you are to the win, you want to know the maximum number of triples you can form from the tiles in your hand.

Input

The first line contains two integers integer nn and mm (1≤n,m≤1061≤n,m≤106) — the number of tiles in your hand and the number of tiles types.

The second line contains integers a1,a2,…,ana1,a2,…,an (1≤ai≤m1≤ai≤m), where aiai denotes the numbe