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머리가..굳어..머리가..굳어..머리가...... 13. Roman to Integer Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X 10L 50C 100D 500M 1000For example, 2 is written as II in Roman numeral, just two ones added together. 12 is written as XII, which is simply X + II. The numbe..

9. Palindrome Number Given an integer x, return true if x is a palindrome, and false otherwise. Example 1:Input: x = 121Output: trueExplanation: 121 reads as 121 from left to right and from right to left.Example 2:Input: x = -121Output: falseExplanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.Example 3:Input: x = 10Output: falseEx..

1. Two Sum  Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.You may assume that each input would have exactly one solution, and you may not use the same element twice.You can return the answer in any order. Example 1:Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums[0] + nums[1] == 9, we return [0,..