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Given s1, s2, s3, find whether s3 is formed by the interleaving of s1and s2. Example 1: Example 2: 给定字符串s1, s2, s3，求s3是否可以由s1和s2交错形成。 解法：DP动态规划， 递推公式为 阅读全文
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Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible representati 阅读全文
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Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x. You should preserve the 阅读全文
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Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. Example 1: Example 2: Follow up: A 阅读全文
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Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of the subtree have the same value. For example:Given 阅读全文
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Given a binary tree, find the length of the longest path where each node in the path has the same value. This path may or may not pass through the roo 阅读全文
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Given two strings A and B, find the minimum number of times A has to be repeated such that B is a substring of it. If no such solution, return -1. For 阅读全文
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In this problem, a rooted tree is a directed graph such that, there is exactly one node (the root) for which all other nodes are descendants of this n 阅读全文