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문제 링크: https://leetcode.com/problems/maximum-69-number/ 문제 You are given a positive integer num consisting only of digits 6 and 9. Return the maximum number you can get by changing at most one digit (6 becomes 9, and 9 becomes 6). 조건 1

문제 링크: https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/ 문제 You are given an array of strings words. Each element of words consists of two lowercase English letters. Create the longest possible palindrome by selecting some elements from words and concatenating them in any order. Each element can be selected at most once. Return the length of the longest palindro..

문제 링크: https://leetcode.com/problems/minimum-genetic-mutation/ 문제 A gene string can be represented by an 8-character long string, with choices from 'A', 'C', 'G', and 'T'. Suppose we need to investigate a mutation from a gene string start to a gene string end where one mutation is defined as one single character changed in the gene string. For example, "AACCGGTT" --> "AACCGGTA" is one mutation. ..

문제 링크: https://leetcode.com/problems/toeplitz-matrix/ 문제 Given an m x n matrix, return true if the matrix is Toeplitz. Otherwise, return false. A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same elements. 조건 m == matrix.length n == matrix[i].length 1

문제 링크: https://leetcode.com/problems/continuous-subarray-sum/ 문제 Given an integer array nums and an integer k, return true if nums has a continuous subarray of size at least two whose elements sum up to a multiple of k, or false otherwise. An integer x is a multiple of k if there exists an integer n such that x = n * k. 0 is always a multiple of k. 조건 1

문제 링크: https://leetcode.com/problems/check-if-two-string-arrays-are-equivalent/ 문제 Given two string arrays word1 and word2, return true if the two arrays represent the same string, and false otherwise. A string is represented by an array if the array elements concatenated in order forms the string. 조건 1

문제 링크: https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/ 문제 You are given an array of strings arr. A string s is formed by the concatenation of a subsequence of arr that has unique characters. Return the maximum possible length of s. A subsequence is an array that can be derived from another array by deleting some or no elements without changing the or..

문제 링크: https://leetcode.com/problems/contains-duplicate-ii/ 문제 Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j)