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Given an array A of strings, find any smallest string that contains each string in A as a substring. We may assume that no string in A is substring of 阅读全文
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Given a string S that only contains "I" (increase) or "D" (decrease), let N = S.length. Return any permutation A of [0, 1, ..., N] such that for all i 阅读全文
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Preorder: Approach #1: Recurisive. Approach #2: Iteratively.[Java] Approach #3: Morris Traversal.[C++] Using Morris Traversal can don't use recurisive 阅读全文
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We are given an array A of N lowercase letter strings, all of the same length. Now, we may choose any set of deletion indices, and for each string, we 阅读全文
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Given an array A of integers, return true if and only if it is a valid mountain array. Recall that A is a mountain array if and only if: A.length >= 3 阅读全文