Let Code Day68 starting from scratch "709. To Lower Case"

Overview

It seems that coding tests are conducted overseas in interviews with engineers, and in many cases, the main thing is to implement specific functions and classes according to the theme.

Apparently, many engineers take measures on the site called LetCode.

It is a site that trains the algorithmic power that can withstand the coding test that is done in the early story, and it is an inevitable path for those who want to build a career at an overseas tech company.

I wrote it in a big way, but I have no plans to have such an interview at the moment.

However, as an IT engineer, it would be better to have the same level of algorithm power as a person, so I would like to solve the problem irregularly and write down the method I thought at that time as a memo.

Leetcode

I'm solving it with Python3.

Leet Code Table of Contents Starting from Zero

Last time Leet Code Day67 starting from zero "1486. XOR Operation in an Array"

Right now, I'm prioritizing the Medium of the Top 100 Liked Questions. I solved all Easy, so if you are interested, please go to the table of contents.

Twitter I'm doing it.

** Technical Blog Started! !! ** ** I think the technology will write about LetCode, Django, Nuxt, and so on. ** This is faster to update **, so please bookmark it!

problem

709. To Lower Case The difficulty level is Easy.

The problem is that we implement a function ToLowerCase () that has the string parameter str and returns the same string in lowercase.

Example 1:

Input: "Hello" Output: "hello"

Example 2:

Input: "here" Output: "here"

Example 3:

Input: "LOVELY" Output: "lovely"

solution

class Solution:
    def toLowerCase(self, str: str) -> str:
        return str.lower()
# Runtime: 24 ms, faster than 91.12% of Python3 online submissions for To Lower Case.
# Memory Usage: 14 MB, less than 15.17% of Python3 online submissions for To Lower Case.

If you know lower, you can write it like this, but what if you don't know it and you don't have an environment to look it up, or if you solve it without using built-in functions, you will be asked in an actual interview.

Considering such a situation, it is easy, but it seems to use my head unexpectedly.

What came to my mind was how to manage with a dictionary. It stores uppercase letters in key and lowercase letters in value, and turns it with a for statement to change it to the corresponding element of value if there is an element corresponding to key. However, I thought that another thing that came to my mind might be something that uses Unicode conversion, so I implemented that this time.

class Solution:
    def toLowerCase(self, str: str) -> str:
        ans = ''
        for s in str:
            if ord(s) >=  ord('A') and ord(s) <= ord('Z'):
                ans +=chr(ord(s) - (ord('A') - ord('a')))
            else:
                ans += s
        return ans
# Runtime: 28 ms, faster than 71.56% of Python3 online submissions for To Lower Case.
# Memory Usage: 13.8 MB, less than 69.29% of Python3 online submissions for To Lower Case.

Use the ʻord functionto convert to Unicode Unicode points and compare. If that value is within the range, subtract Unicode points, and finally convert it to a character string using thechr function and assign it to ʻans. In other cases, the idea is that it is originally lowercase, so you can just substitute it.

As a supplement, the Unicode list is as follows. Unicode list 0000-0FFF

It was very interesting because I thought about it from a perspective that I wouldn't normally think of. So that's it for this time. Thank you for your hard work.

Recommended Posts

Let Code Day68 starting from scratch "709. To Lower Case"
Let Code Day75 starting from scratch "15.3 Sum"
Let Code Day 29 "46. Permutations" starting from scratch
Let Code Day 41 "394. Decode String" starting from scratch
Let Code Day 25 "70. Climbing Stairs" starting from scratch
Let Code Day69 starting from scratch "279. Perfect Squares"
Let Code Day 34 starting from scratch "118. Pascal's Triangle"
Let Code Day85 starting from scratch "6. ZigZag Conversion"
Let Code Day20 starting from scratch "134. Gas Station"
Let Code Day 88 "139. Word Break" starting from scratch
Let Code Day 28 "198. House Robber" starting from scratch
Let Code Day 39 "494. Target Sum" starting from scratch
Let Code Day 36 "155. Min Stack" starting from scratch
Let Code Day 17 "169. Majority Element" starting from scratch
Let Code Day 33 "1. Two Sum" starting from scratch
Let Code Day 23 "226. Invert Binary Tree" starting from scratch
Let Code Day8 starting from scratch "1302. Deepest Leaves Sum"
Let Code Day 22 starting from scratch "141. Linked List Cycle"
Let Code Day74 starting from zero "12. Integer to Roman"
Let Code Day 32 "437. Path Sum III" starting from scratch
Let Code Day 46 starting from scratch "406. Queue Reconstruction by Height"
Let Code Day 31 starting from scratch "581. Shortest Unsorted Continuous Subarray"
Let Code Day 38 starting from scratch "208. Implement Trie (Prefix Tree)"
Let Code Day3 starting from scratch "1313. Decompress Run-Length Encoded List"
Let Code Day 65 "560. Subarray Sum Equals K" starting from scratch
Let Code Day4 starting from scratch "938. Range Sum of BST"
Let Code Day 77 starting from scratch "1502. Can Make Arithmetic Progression From Sequence"
Let Code Day16 Starting from Zero "344. Reverse String"
Let Code Day49 starting from zero "1323. Maximum 69 Number"
Let Code Day89 "62. Unique Paths" Starting from Zero
Let Code Day 55 "22. Generate Parentheses" Starting from Zero
Let Code Day 13 "338. Counting Bits" Starting from Zero
Let Code Day71 Starting from Zero "1496. Path Crossing"
Let Code Day 61 "7. Reverse Integer" starting from zero
Let Code Day 82 "392. Is Subsequence" Starting from Zero
Let Code Day51 Starting from Zero "647. Palindromic Substrings"
Let Code Day 50 "739. Daily Temperatures" Starting from Zero
Let Code Day 15 "283. Move Zeroes" starting from zero
Let Code Day14 starting from zero "136. Single Number"
Let Code Day 40 Starting from Zero "114. Flatten Binary Tree to Linked List"
Let Code Day 9 "701. Insert into a Binary Search Tree" starting from scratch
Let Code Day 66 "438. Find All Anagrams in a String" starting from scratch
Let Code Day6 Starting from Zero "1342. Number of Steps to Reduce a Number to Zero"
Let Code Day 43 "5. Longest Palindromic Substring" Starting from Zero
Let Code Day57 Starting from Zero "35. Search Insert Position"
Let Code Day47 Starting from Zero "14. Longest Common Prefix"
Let Code Day78 Starting from Zero "206. Reverse Linked List"
Let Code Day 19 Starting from Zero "121. Best Time to Buy and Sell Stock"
Let Code Day 44 "543. Diameter of Binary Tree" starting from zero
Let Code Day 64 starting from zero "287. Find the Duplicate Number"
Let Code Day 84 starting from zero "142. Linked List Cycle II"
Let Code Day24 Starting from Zero "21. Merge Two Sorted Lists"
Let Code Day12 Starting from Zero "617. Merge Two Binary Trees"
Let Code Day2 Starting from Zero "1108. Defanging an IP Address"
Let Code Day70 Starting from Zero "295. Find Median from Data Stream"
Let Code Day81 "347. Top K Frequent Elements" Starting from Zero
Let Code Day48 Starting from Zero "26. Remove Duplicates from Sorted Array"
Let Code Day87 Starting from Zero "1512. Number of Good Pairs"
Let Code Day 79 "1282. Group the People Given the Group Size They Belong To" Starting from Zero
Let Code Day54 Starting from Zero "1290. Convert Binary Number in a Linked List to Integer"
Let Code Day67 Starting from Zero "1486. XOR Operation in an Array"