搞定动态规划，横扫大厂 offer

Posted 2021-04-18 HJ说

程序员晋升上也能胜人一筹。","0:\"%23111f2c\"|27:\"12\"|31:2"],[20,"\n","24:\"g8IY\"|7:3"],[20,"\n","24:\"o4oS\"|7:3"],[20,"但即使知道它很重要，很多人一想起来依然是“脑壳痛”，在工作和面试中也很难实践应用，问题出在哪了？","27:\"12\""],[20,"\n","24:\"wzjp\"|7:3"],[20,"\n","24:\"fVmp\"|7:3"],[20,"很简单：不理解动规的思想，无法掌握解题套路。","27:\"12\"|8:1"],[20,"\n","24:\"JSdk\"|7:3"],[20,"\n","24:\"8IUC\"|7:3"],[20,"作为一种","0:\"%23494949\"|27:\"12\""],[20,"高级技术思想","27:\"12\""],[20,"，动规","0:\"%23494949\"|27:\"12\""],[20,"是从一系列算法中演进而来的。求解动态规划的核心问题其实就是穷举，但穷举和动态规划在真正用的时候还是有区别的，","27:\"12\""],[20,"首先要解决的是，什么样的问题要用动态规划，怎么用？","27:\"12\"|8:1"],[20,"\n","24:\"RkRo\"|7:3"],[20,"\n","24:\"gCHV\""],[20,"举个例子，在实际工作中，除非你碰到的问题是简单到找出一个数组中最大的值这样，对这种问题来说，你可以对数组进行排序，然后取数组头或尾部的元素，如果觉得麻烦，你也可以直接遍历得到最值。不然的话，","27:\"12\""],[20,"你就得考虑使用动态规划来解决这个问题了","27:\"12\"|8:1"],[20,"。这样的问题一般都会让你求最大子数组、求最长递增子数组、求最长递增子序列或求最长公共子串、子序列等等。不知道你发现没有，这些问题里都包含一个“最”字，如果出现了这个字，你就该警惕它是否是动归问题。","27:\"12\""],[20,"\n","24:\"GkjB\""],[20,"\n","24:\"Qkhy\""],[20,"具体怎么判断呢？你可以按照这样的思考顺序来解决问题：","27:\"12\"|8:1"],[20,"\n","24:\"wR9h\""],[20,"\n","24:\"Uzwg\""],[20,"1.优先考虑使用贪心算法的可能性；","27:\"12\""],[20,"\n","24:\"KosF\""],[20,"2.然后是暴力递归进行穷举（但这里的数据规模不大）；","27:\"12\""],[20,"\n","24:\"7eSL\""],[20,"3.还是不行呢？选择动态规划！","27:\"12\""],[20,"\n","24:\"e8tk\""],[20,"\n","24:\"U84Y\""],[20,"那么，当我们遇到一个算法问题，到底是否该使用动态规划来求解呢？可以参考这","27:\"12\""],[20," 5 大特点：","27:\"12\"|8:1"],[20,"\n","24:\"LscY\""],[20,"\n","24:\"BWX2\""],[20,"求最优解问题（最大值和最小值）","27:\"12\""],[20,"\n","24:\"7xYO\"|27:\"12\"|bullet-id:\"k8ti\"|bullet:\"circle\""],[20,"求可行性（True 或 False）","27:\"12\""],[20,"\n","24:\"vKPg\"|27:\"12\"|bullet-id:\"k8ti\"|bullet:\"circle\""],[20,"求方案总数","27:\"12\""],[20,"\n","24:\"0Ik7\"|27:\"12\"|bullet-id:\"k8ti\"|bullet:\"circle\""],[20,"数据结构不可排序（Unsortable）","27:\"12\""],[20,"\n","24:\"TpFj\"|27:\"12\"|bullet-id:\"k8ti\"|bullet:\"circle\""],[20,"算法不可使用交换（Non-swappable）","27:\"12\""],[20,"\n","24:\"E1Y7\"|27:\"12\"|bullet-id:\"k8ti\"|bullet:\"circle\""],[20,"\n","24:\"KvKo\""],[20,"如果面试题目出现这些特征，那么在 90% 的情况下你都能断言它就是一个动归问题。","27:\"12\""],[20,"\n","24:\"7yan\"|7:3"],[20,"\n","24:\"iWGY\""],[20,"这套判断动规问题的思路，来自于卢誉声，","27:\"12\""],[20,"Autodesk 核心数据平台和计算平台资深工程师，除此之外，我还找到了他整理的","27:\"12\"|31:2"],[20,"「动态规划知识结构图」，可以收藏

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