Merge Level2 before all problems solved.

.gitignore

@@ -0,0 +1,148 @@
+
+# Created by https://www.toptal.com/developers/gitignore/api/macos,webstorm
+# Edit at https://www.toptal.com/developers/gitignore?templates=macos,webstorm
+
+
+.idea/*
+
+
+### macOS ###
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### WebStorm ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# AWS User-specific
+.idea/**/aws.xml
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# SonarLint plugin
+.idea/sonarlint/
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### WebStorm Patch ###
+# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+
+# *.iml
+# modules.xml
+# .idea/misc.xml
+# *.ipr
+
+# Sonarlint plugin
+# https://plugins.jetbrains.com/plugin/7973-sonarlint
+.idea/**/sonarlint/
+
+# SonarQube Plugin
+# https://plugins.jetbrains.com/plugin/7238-sonarqube-community-plugin
+.idea/**/sonarIssues.xml
+
+# Markdown Navigator plugin
+# https://plugins.jetbrains.com/plugin/7896-markdown-navigator-enhanced
+.idea/**/markdown-navigator.xml
+.idea/**/markdown-navigator-enh.xml
+.idea/**/markdown-navigator/
+
+# Cache file creation bug
+# See https://youtrack.jetbrains.com/issue/JBR-2257
+.idea/$CACHE_FILE$
+
+# CodeStream plugin
+# https://plugins.jetbrains.com/plugin/12206-codestream
+.idea/codestream.xml
+
+# End of https://www.toptal.com/developers/gitignore/api/macos,webstorm

README.md

@@ -19,9 +19,9 @@
 
 ## Level 1 ✅ 
 
-풀이 완료(2022년 1월) 
-
-
+- 전체 문제 수: 54문제
+- 풀이 문제 수: 54문제
+- 풀이 완료 시점: 2022년 1월
 
 ## Level 2 👨🏻‍💻(풀이 중..)
 

level-2/124-나라의-숫자.js

@@ -0,0 +1,29 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+//정답 1
+function solution(n) {
+    var answer = '';
+    const oneTwoFour = ['4','1','2']
+    while (n>0){
+        const remainder = n % 3
+        answer = oneTwoFour[remainder] + answer;
+        n = Math.floor((n-1)/3) //나누어떨어지지 않을 때에도 -1해도 상관없음
+    }
+    return answer;
+}
+
+//정답 2
+function solution(n) {
+    var answer = '';
+    const oneTwoFour = ['4','1','2']
+    while (n>0){
+        const remainder = n % 3
+        answer = oneTwoFour[remainder] + answer;
+        if(remainder === 0){
+            n = Math.floor((n-1)/3)
+        }else{
+            n = Math.floor(n/3)
+        }
+    }
+    return answer;
+}

level-2/H-Index.js

@@ -0,0 +1,24 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+//정답 1
+function solution(citations) {
+    var answer = 0;
+    citations.sort((a,b)=>b-a)
+    let h = 0
+    while(h+1<=citations[h]) h++
+    answer = h
+    return answer;
+}
+
+//정답 2
+function solution(citations) {
+    var answer = 0;
+    let h = 0
+    let length = 0
+    while(length >= h){
+        h++
+        length = citations.filter(citation => citation>=h).length
+    }
+    answer = h - 1
+    return answer;
+}

level-2/JadenCase-문자열-만들기.js

@@ -0,0 +1,8 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+function solution(s) {
+    var answer = ''
+    answer = s.split(' ').map(word=> word.charAt(0).toUpperCase() + word.substring(1).toLowerCase()).join(' ')
+    //word[0]은 빈 문자열을 만나면 undefined를,  word.charAt(0)은 빈 문자열을 만나면 빈 문자열을 반환한다.
+    return answer;
+}

level-2/N개의-최소공배수.js

@@ -0,0 +1,18 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+function solution(arr) {
+    var answer = 0;
+    answer = arr.reduce((a,b)=> leastCommonMultiple(a,b), 1)
+    return answer;
+}
+function leastCommonMultiple(a, b){
+    return a * b / greatestCommonDivisor(a, b)
+}
+function greatestCommonDivisor(a, b){
+    while(b > 0){
+        let r = a % b;
+        a = b;
+        b = r;
+    }
+    return a;
+}

level-2/[1차]-캐시.js

@@ -0,0 +1,20 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+function solution(cacheSize, cities) {
+    var answer = 0;
+    let cache = []
+    if (cacheSize === 0) return 5 * cities.length
+    for (const city of cities) {
+        const cityLC = city.toLowerCase()
+        if (cache.includes(cityLC)) {
+            cache.splice(cache.indexOf(cityLC), 1)
+            cache.unshift(cityLC)
+            answer += 1
+        } else {
+            if (cache.length >= cacheSize) cache.pop()
+            cache.unshift(cityLC)
+            answer += 5
+        }
+    }
+    return answer;
+}

level-2/가장-큰-수.js

@@ -0,0 +1,14 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+function solution(numbers) {
+    var answer = '';
+    numbers.sort(sortFunc)
+    answer = numbers.join('')
+    if(answer[0] === '0') return '0'
+    return answer;
+}
+const sortFunc =  (a,b) =>{
+    const compareA = parseInt(a.toString() + b.toString())
+    const compareB = parseInt(b.toString() + a.toString())
+    return compareB - compareA
+}

level-2/괄호-변환.js

@@ -0,0 +1,63 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+//정답 1
+function solution(p) {
+    if(p.length === 0) return p
+    let bracketCount = 0
+    let isURight = true
+    for(let i=0; i<p.length; i++){
+        bracketCount = p[i] === '(' ? bracketCount + 1 : bracketCount - 1
+        if(bracketCount < 0) isURight = false
+        if(bracketCount === 0){
+            const [u, v] = [p.slice(0,i+1), p.slice(i+1)]
+            if(isURight){
+                return u + solution(v)
+            }else{
+                let emptyString = '(' + solution(v) + ')'
+                const slicedReversedString = u
+                    .slice(1,u.length-1)
+                    .split('')
+                    .map(bracket=> bracket === '(' ? ')' : '(')
+                    .join('')
+                return emptyString + slicedReversedString
+            }
+        }
+    }
+}
+
+//정답 2
+function solution(p) {
+    if(p.length === 0){
+        return p
+    }else{
+        const sliceIndex = balancedIndex(p)
+        const [u, v] = [p.slice(0,sliceIndex+1), p.slice(sliceIndex+1)]
+        if(isRight(u)){
+            return u + solution(v)
+        }else{
+            let emptyString = '(' + solution(v) + ')'
+            const slicedReversedString = u
+                .slice(1,u.length-1)
+                .split('')
+                .map(bracket=> bracket === '(' ? ')' : '(')
+                .join('')
+            return emptyString + slicedReversedString
+        }
+    }
+}
+const isRight = (str) => {
+    if(str[0] === ')') return false
+    let stack = 0
+    for(let i=0; i<str.length; i++){
+        stack = str[i] === '(' ? stack + 1 : stack - 1
+        if(stack < 0) return false
+    }
+    return stack === 0
+}
+const balancedIndex = (str) =>{
+    let count = 0
+    for(let i=0; i<str.length; i++){
+        count = str[i] === '(' ? count + 1 :  count - 1
+        if(count === 0) return i
+    }
+}

level-2/괄호-회전하기.js

@@ -0,0 +1,36 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+function solution(s) {
+    let answer = 0;
+    let sArr = s.split('')
+    if(isRight(sArr.join(''))) answer += 1
+    for(let i=0; i<sArr.length - 1; i++){
+        sArr.push(sArr.shift())
+        if(isRight(sArr.join(''))) answer += 1
+    }
+    return answer;
+}
+function isRight(str){
+    const bracketOpen = ['[', '{', '('], bracketClose = [']', '}', ')']
+    let status = [{open: false, openOrder: []}, {open: false, openOrder: []}, {open: false, openOrder: []}]
+    for(let sIndex=0; sIndex<str.length; sIndex++){
+        for(let bIndex = 0; bIndex<3; bIndex++){
+            if(str[sIndex] === bracketOpen[bIndex]){
+                status[bIndex].open = true
+                status[bIndex].openOrder.push(sIndex)
+            }
+            if(str[sIndex] === bracketClose[bIndex]){
+                if(status[bIndex].openOrder.length > 0){
+                    if(status.filter(check=>check.open && check.openOrder[check.openOrder.length - 1] > status[bIndex].openOrder[status[bIndex].openOrder.length - 1]).length > 0)
+                        return false //먼저 닫혀야 하는 괄호보다 먼저 닫힘
+                    status[bIndex].openOrder.pop()
+                    status[bIndex].open = false
+                }else{
+                    return false //열리기 전에 닫힘
+                }
+            }
+        }
+    }
+    for(let i=0; i<3; i++) if(status[i].open) return false //닫히지 않은 괄호가 있음
+    return true
+}