diff --git a/README.md b/README.md
index f83a6d1..cb30a60 100644
--- a/README.md
+++ b/README.md
@@ -103,7 +103,7 @@
 ### Level 2 👨🏻‍💻(풀이 중..)
 
 - 전체 문제 수: 64문제
-- 풀이 문제 수: 45문제
+- 풀이 문제 수: 46문제
 - 풀이 완료 예상 시점: 2022년 4월 중
 
 | 번호 | 문제 출처 | 풀이 |
@@ -116,48 +116,49 @@
 | 6 | [[1차] 캐시](https://programmers.co.kr/learn/courses/30/lessons/17680) | [[1차]-캐시.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/[1차]-캐시.js) |
 | 7 | [[3차] n진수 게임](https://programmers.co.kr/learn/courses/30/lessons/17687) | [[3차]-n진수-게임.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/[3차]-n진수-게임.js) |
 | 8 | [[3차] 파일명 정렬](https://programmers.co.kr/learn/courses/30/lessons/17686) | [[3차]-파일명-정렬.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/[3차]-파일명-정렬.js) |
-| 9 | [가장 큰 수](https://programmers.co.kr/learn/courses/30/lessons/42746) | [가장-큰-수.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/가장-큰-수.js) |
-| 10 | [가장 큰 정사각형 찾기](https://programmers.co.kr/learn/courses/30/lessons/12905) | [가장-큰-정사각형-찾기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/가장-큰-정사각형-찾기.js) |
-| 11 | [거리두기 확인하기](https://programmers.co.kr/learn/courses/30/lessons/81302) | [거리두기-확인하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/거리두기-확인하기.js) |
-| 12 | [괄호 변환](https://programmers.co.kr/learn/courses/30/lessons/60058) | [괄호-변환.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/괄호-변환.js) |
-| 13 | [괄호 회전하기](https://programmers.co.kr/learn/courses/30/lessons/76502) | [괄호-회전하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/괄호-회전하기.js) |
-| 14 | [구명보트](https://programmers.co.kr/learn/courses/30/lessons/42885) | [구명보트.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/구명보트.js) |
-| 15 | [기능개발](https://programmers.co.kr/learn/courses/30/lessons/42586) | [기능개발.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/기능개발.js) |
-| 16 | [다리를 지나는 트럭](https://programmers.co.kr/learn/courses/30/lessons/42583) | [다리를-지나는-트럭.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/다리를-지나는-트럭.js) |
-| 17 | [다음 큰 숫자](https://programmers.co.kr/learn/courses/30/lessons/12911) | [다음-큰-숫자.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/다음-큰-숫자.js) |
-| 18 | [땅따먹기](https://programmers.co.kr/learn/courses/30/lessons/12913) | [땅따먹기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/땅따먹기.js) |
-| 19 | [멀쩡한 사각형](https://programmers.co.kr/learn/courses/30/lessons/62048) | [멀쩡한-사각형.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/멀쩡한-사각형.js) |
-| 20 | [메뉴 리뉴얼](https://programmers.co.kr/learn/courses/30/lessons/72411) | [메뉴-리뉴얼.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/메뉴-리뉴얼.js) |
-| 21 | [문자열 압축](https://programmers.co.kr/learn/courses/30/lessons/60057) | [문자열-압축.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/문자열-압축.js) |
-| 22 | [삼각 달팽이](https://programmers.co.kr/learn/courses/30/lessons/68645) | [삼각-달팽이.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/삼각-달팽이.js) |
-| 23 | [소수 찾기](https://programmers.co.kr/learn/courses/30/lessons/42839) | [소수-찾기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/소수-찾기.js) |
-| 24 | [수식 최대화](https://programmers.co.kr/learn/courses/30/lessons/67257) | [수식-최대화.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/수식-최대화.js) |
-| 25 | [숫자의 표현](https://programmers.co.kr/learn/courses/30/lessons/12924) | [숫자의-표현.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/숫자의-표현.js) |
-| 26 | [스킬트리](https://programmers.co.kr/learn/courses/30/lessons/49993) | [스킬트리.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/스킬트리.js) |
-| 27 | [영어 끝말잇기](https://programmers.co.kr/learn/courses/30/lessons/12981) | [영어-끝말잇기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/영어-끝말잇기.js) |
-| 28 | [예상 대진표](https://programmers.co.kr/learn/courses/30/lessons/12985) | [예상-대진표.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/예상-대진표.js) |
-| 29 | [오픈채팅방 ](https://programmers.co.kr/learn/courses/30/lessons/42888) | [오픈채팅방.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/오픈채팅방.js) |
-| 30 | [올바른 괄호](https://programmers.co.kr/learn/courses/30/lessons/12909) | [올바른-괄호.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/올바른-괄호.js) |
-| 31 | [위장](https://programmers.co.kr/learn/courses/30/lessons/42578) | [위장.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/위장.js) |
-| 32 | [점프와 순간 이동](https://programmers.co.kr/learn/courses/30/lessons/12980) | [점프와-순간-이동.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/점프와-순간-이동.js) |
-| 33 | [조이스틱](https://programmers.co.kr/learn/courses/30/lessons/42860) | [조이스틱.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/조이스틱.js) |
-| 34 | [짝지어 제거하기](https://programmers.co.kr/learn/courses/30/lessons/12973) | [짝지어-제거하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/짝지어-제거하기.js) |
-| 35 | [최댓값과 최솟값](https://programmers.co.kr/learn/courses/30/lessons/12939) | [최댓값과-최솟값.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/최댓값과-최솟값.js) |
-| 36 | [최솟값 만들기](https://programmers.co.kr/learn/courses/30/lessons/12941) | [최솟값-만들기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/최솟값-만들기.js) |
-| 37 | [카펫](https://programmers.co.kr/learn/courses/30/lessons/42842) | [카펫.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/카펫.js) |
-| 38 | [큰 수 만들기](https://programmers.co.kr/learn/courses/30/lessons/42883) | [큰-수-만들기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/큰-수-만들기.js) |
-| 39 | [타겟 넘버](https://programmers.co.kr/learn/courses/30/lessons/43165) | [타겟-넘버.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/타겟-넘버.js) |
-| 40 | [튜플](https://programmers.co.kr/learn/courses/30/lessons/64065) | [튜플.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/튜플.js) |
-| 41 | [프린터](https://programmers.co.kr/learn/courses/30/lessons/42587) | [프린터.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/프린터.js) |
-| 42 | [피보나치 수](https://programmers.co.kr/learn/courses/30/lessons/12945) | [피보나치-수.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/피보나치-수.js) |
-| 43 | [행렬 테두리 회전하기](https://programmers.co.kr/learn/courses/30/lessons/77485) | [행렬-테두리-회전하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/행렬-테두리-회전하기.js) |
-| 44 | [행렬의 곱셈](https://programmers.co.kr/learn/courses/30/lessons/12949) | [행렬의-곱셈.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/행렬의-곱셈.js) |
-| 45 | [후보키](https://programmers.co.kr/learn/courses/30/lessons/42890) | [후보키.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/후보키.js) |
+| 9 | [n^2 배열 자르기](https://programmers.co.kr/learn/courses/30/lessons/87390) | [n^2-배열-자르기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/n^2-배열-자르기.js) |
+| 10 | [가장 큰 수](https://programmers.co.kr/learn/courses/30/lessons/42746) | [가장-큰-수.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/가장-큰-수.js) |
+| 11 | [가장 큰 정사각형 찾기](https://programmers.co.kr/learn/courses/30/lessons/12905) | [가장-큰-정사각형-찾기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/가장-큰-정사각형-찾기.js) |
+| 12 | [거리두기 확인하기](https://programmers.co.kr/learn/courses/30/lessons/81302) | [거리두기-확인하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/거리두기-확인하기.js) |
+| 13 | [괄호 변환](https://programmers.co.kr/learn/courses/30/lessons/60058) | [괄호-변환.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/괄호-변환.js) |
+| 14 | [괄호 회전하기](https://programmers.co.kr/learn/courses/30/lessons/76502) | [괄호-회전하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/괄호-회전하기.js) |
+| 15 | [구명보트](https://programmers.co.kr/learn/courses/30/lessons/42885) | [구명보트.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/구명보트.js) |
+| 16 | [기능개발](https://programmers.co.kr/learn/courses/30/lessons/42586) | [기능개발.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/기능개발.js) |
+| 17 | [다리를 지나는 트럭](https://programmers.co.kr/learn/courses/30/lessons/42583) | [다리를-지나는-트럭.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/다리를-지나는-트럭.js) |
+| 18 | [다음 큰 숫자](https://programmers.co.kr/learn/courses/30/lessons/12911) | [다음-큰-숫자.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/다음-큰-숫자.js) |
+| 19 | [땅따먹기](https://programmers.co.kr/learn/courses/30/lessons/12913) | [땅따먹기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/땅따먹기.js) |
+| 20 | [멀쩡한 사각형](https://programmers.co.kr/learn/courses/30/lessons/62048) | [멀쩡한-사각형.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/멀쩡한-사각형.js) |
+| 21 | [메뉴 리뉴얼](https://programmers.co.kr/learn/courses/30/lessons/72411) | [메뉴-리뉴얼.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/메뉴-리뉴얼.js) |
+| 22 | [문자열 압축](https://programmers.co.kr/learn/courses/30/lessons/60057) | [문자열-압축.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/문자열-압축.js) |
+| 23 | [삼각 달팽이](https://programmers.co.kr/learn/courses/30/lessons/68645) | [삼각-달팽이.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/삼각-달팽이.js) |
+| 24 | [소수 찾기](https://programmers.co.kr/learn/courses/30/lessons/42839) | [소수-찾기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/소수-찾기.js) |
+| 25 | [수식 최대화](https://programmers.co.kr/learn/courses/30/lessons/67257) | [수식-최대화.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/수식-최대화.js) |
+| 26 | [숫자의 표현](https://programmers.co.kr/learn/courses/30/lessons/12924) | [숫자의-표현.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/숫자의-표현.js) |
+| 27 | [스킬트리](https://programmers.co.kr/learn/courses/30/lessons/49993) | [스킬트리.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/스킬트리.js) |
+| 28 | [영어 끝말잇기](https://programmers.co.kr/learn/courses/30/lessons/12981) | [영어-끝말잇기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/영어-끝말잇기.js) |
+| 29 | [예상 대진표](https://programmers.co.kr/learn/courses/30/lessons/12985) | [예상-대진표.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/예상-대진표.js) |
+| 30 | [오픈채팅방 ](https://programmers.co.kr/learn/courses/30/lessons/42888) | [오픈채팅방.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/오픈채팅방.js) |
+| 31 | [올바른 괄호](https://programmers.co.kr/learn/courses/30/lessons/12909) | [올바른-괄호.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/올바른-괄호.js) |
+| 32 | [위장](https://programmers.co.kr/learn/courses/30/lessons/42578) | [위장.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/위장.js) |
+| 33 | [점프와 순간 이동](https://programmers.co.kr/learn/courses/30/lessons/12980) | [점프와-순간-이동.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/점프와-순간-이동.js) |
+| 34 | [조이스틱](https://programmers.co.kr/learn/courses/30/lessons/42860) | [조이스틱.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/조이스틱.js) |
+| 35 | [짝지어 제거하기](https://programmers.co.kr/learn/courses/30/lessons/12973) | [짝지어-제거하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/짝지어-제거하기.js) |
+| 36 | [최댓값과 최솟값](https://programmers.co.kr/learn/courses/30/lessons/12939) | [최댓값과-최솟값.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/최댓값과-최솟값.js) |
+| 37 | [최솟값 만들기](https://programmers.co.kr/learn/courses/30/lessons/12941) | [최솟값-만들기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/최솟값-만들기.js) |
+| 38 | [카펫](https://programmers.co.kr/learn/courses/30/lessons/42842) | [카펫.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/카펫.js) |
+| 39 | [큰 수 만들기](https://programmers.co.kr/learn/courses/30/lessons/42883) | [큰-수-만들기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/큰-수-만들기.js) |
+| 40 | [타겟 넘버](https://programmers.co.kr/learn/courses/30/lessons/43165) | [타겟-넘버.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/타겟-넘버.js) |
+| 41 | [튜플](https://programmers.co.kr/learn/courses/30/lessons/64065) | [튜플.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/튜플.js) |
+| 42 | [프린터](https://programmers.co.kr/learn/courses/30/lessons/42587) | [프린터.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/프린터.js) |
+| 43 | [피보나치 수](https://programmers.co.kr/learn/courses/30/lessons/12945) | [피보나치-수.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/피보나치-수.js) |
+| 44 | [행렬 테두리 회전하기](https://programmers.co.kr/learn/courses/30/lessons/77485) | [행렬-테두리-회전하기.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/행렬-테두리-회전하기.js) |
+| 45 | [행렬의 곱셈](https://programmers.co.kr/learn/courses/30/lessons/12949) | [행렬의-곱셈.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/행렬의-곱셈.js) |
+| 46 | [후보키](https://programmers.co.kr/learn/courses/30/lessons/42890) | [후보키.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-2/후보키.js) |
 
 ### Level 3 👨🏻‍💻(풀이 중..)
 
 - 전체 문제 수: 52문제
-- 풀이 문제 수: 8문제
+- 풀이 문제 수: 9문제
 - 풀이 완료 예상 시점: 2022년 8월 중
 
 | 번호 | 문제 출처 | 풀이 |
@@ -166,10 +167,11 @@
 | 2 | [N-Queen](https://programmers.co.kr/learn/courses/30/lessons/12952) | [N-Queen.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/N-Queen.js) |
 | 3 | [가장 먼 노드](https://programmers.co.kr/learn/courses/30/lessons/49189) | [가장-먼-노드.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/가장-먼-노드.js) |
 | 4 | [네트워크](https://programmers.co.kr/learn/courses/30/lessons/43162) | [네트워크.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/네트워크.js) |
-| 5 | [베스트앨범](https://programmers.co.kr/learn/courses/30/lessons/42579) | [베스트앨범.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/베스트앨범.js) |
-| 6 | [여행경로](https://programmers.co.kr/learn/courses/30/lessons/43164) | [여행경로.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/여행경로.js) |
-| 7 | [이중우선순위큐](https://programmers.co.kr/learn/courses/30/lessons/42628) | [이중우선순위큐.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/이중우선순위큐.js) |
-| 8 | [입국심사](https://programmers.co.kr/learn/courses/30/lessons/43238) | [입국심사.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/입국심사.js) |
+| 5 | [단속카메라](https://programmers.co.kr/learn/courses/30/lessons/42884) | [단속카메라.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/단속카메라.js) |
+| 6 | [베스트앨범](https://programmers.co.kr/learn/courses/30/lessons/42579) | [베스트앨범.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/베스트앨범.js) |
+| 7 | [여행경로](https://programmers.co.kr/learn/courses/30/lessons/43164) | [여행경로.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/여행경로.js) |
+| 8 | [이중우선순위큐](https://programmers.co.kr/learn/courses/30/lessons/42628) | [이중우선순위큐.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/이중우선순위큐.js) |
+| 9 | [입국심사](https://programmers.co.kr/learn/courses/30/lessons/43238) | [입국심사.js](https://github.com/codeisneverodd/programmers-coding-test/blob/main/level-3/입국심사.js) |
 
 ### Level 4
 
diff --git "a/level-1/\354\206\214\354\210\230-\353\247\214\353\223\244\352\270\260.js" "b/level-1/\354\206\214\354\210\230-\353\247\214\353\223\244\352\270\260.js"
index 524b7a5..d877d04 100644
--- "a/level-1/\354\206\214\354\210\230-\353\247\214\353\223\244\352\270\260.js"
+++ "b/level-1/\354\206\214\354\210\230-\353\247\214\353\223\244\352\270\260.js"
@@ -21,4 +21,32 @@ function isPrime(num) {
         if (num % i === 0) return false
     }
     return true
-}
\ No newline at end of file
+}
+
+//정답 2 - jaewon1676
+// https://programmers.co.kr/learn/courses/30/lessons/12977?language=javascript
+
+function solution(nums) {
+    let len = nums.length, answer = 0;
+  
+    for (let i = 0; i < len - 2; i++) {
+      for (let j = i + 1; j < len - 1; j++) {
+        for (let k = j + 1; k < len; k++) {
+          if (isPrime(nums[i] + nums[j] + nums[k])) {
+            answer++;
+          }
+        }
+      }
+    }
+    return answer;
+}
+  
+const isPrime = (n) => {
+    for (let i = 2; i <= Math.sqrt(n); i++) { //n의 제곱근까지 순회
+      if (n % i === 0) { // 나머지가 0이 나오면 소수가 아니다.
+        return false;
+      }
+    }
+    return true;
+}
+// 세개의 수를 더해야 하기때문에 수 for문 하나당 수 하나를 넣어서 순회하였다.
\ No newline at end of file
diff --git "a/level-1/\354\262\264\354\234\241\353\263\265.js" "b/level-1/\354\262\264\354\234\241\353\263\265.js"
index d3e33b1..e54662b 100644
--- "a/level-1/\354\262\264\354\234\241\353\263\265.js"
+++ "b/level-1/\354\262\264\354\234\241\353\263\265.js"
@@ -60,4 +60,29 @@ function solution(n, lost, reserve) {
     }
     // 체육복 1개 이상을 가진 학생들의 수 반환
     return students.filter((v => v >= 1)).length;
-}
\ No newline at end of file
+}
+
+//정답 3 - jaewon1676
+function solution(n, lost, reserve) {
+    let answer = Array(n).fill(1) // n만큼의 배열을 만들어서 1을 만들어줍니다
+    let cnt = 0;
+    for(let i = 0; i < reserve.length; i++){ // reserve 를 순회하며 체육복 
+        answer[reserve[i]-1] += 1
+    }    
+    for(let i = 0; i < lost.length; i++){ // lost 를 순회하며 체육복 수를 -1 
+        answer[lost[i]-1] -= 1
+    }
+    for(let i = 0; i < n; i++){ // n을 순회하며 앞사람과 뒷사람의 체육복 수를 비교한다.
+        if (answer[i] == 2 && answer[i+1] == 0 || answer[i+1] == 2 && answer[i] == 0){
+            answer[i] = 1
+            answer[i+1] = 1
+        }
+    }
+    for(let i = 0; i < answer.length; i++){
+        (answer[i] >= 1 ? cnt += 1 : null)
+    }
+    return cnt
+  }
+  //그리디 
+  // lost 배열과 reserve 배열을 순회하여 체육복을 추가, 제거 해줍니다.
+  // 그 후에 최종적으로 i부터 n까지 for문을 순회하며 i번쨰 학생과 i+1번째의 학생이 가진 체육복 수를 비교하여 빌려 줄 수 있는지, 빌려줄 수 없는지 확인 합니다.
\ No newline at end of file
diff --git "a/level-2/JadenCase-\353\254\270\354\236\220\354\227\264-\353\247\214\353\223\244\352\270\260.js" "b/level-2/JadenCase-\353\254\270\354\236\220\354\227\264-\353\247\214\353\223\244\352\270\260.js"
index 6bf88ab..7462044 100644
--- "a/level-2/JadenCase-\353\254\270\354\236\220\354\227\264-\353\247\214\353\223\244\352\270\260.js"
+++ "b/level-2/JadenCase-\353\254\270\354\236\220\354\227\264-\353\247\214\353\223\244\352\270\260.js"
@@ -6,4 +6,19 @@ function solution(s) {
     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;
-}
\ No newline at end of file
+}
+
+//정답 2 - jaewon1676
+function solution(s) {
+    s = s.split(' ').map(el => el.split('').map((el, index) => 
+    index == 0 ? el.toUpperCase() : el.toLowerCase()).join('')).join(' ')
+    return s;
+}
+// 문자열을 연습하기에 좋은 문제입니다.
+  
+// s.split(' ') // 띄어쓰기를 기준으로 나눕니다.
+// .map(el => el.split('')) 나눈 덩어리를 다시 요소 하나 하나씩 나눠줍니다 
+// .map((el, index) => index == 0 ? el.toUpperCase() : el.toLowerCase())
+// 덩어리의 요소가 첫번째이면 대문자, 그렇지 않으면 소문자로 변환 해줍니다.    
+// .join('')  작은 배열들을 합쳐줍니다.
+// .join(' ') 큰 배열들을 합쳐줍니다.
\ No newline at end of file
diff --git "a/level-2/n^2-\353\260\260\354\227\264-\354\236\220\353\245\264\352\270\260.js" "b/level-2/n^2-\353\260\260\354\227\264-\354\236\220\353\245\264\352\270\260.js"
new file mode 100644
index 0000000..1fff1ad
--- /dev/null
+++ "b/level-2/n^2-\353\260\260\354\227\264-\354\236\220\353\245\264\352\270\260.js"
@@ -0,0 +1,13 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+//정답 1 - jaewon1676
+function solution (n, left, right) {
+  const answer = [];
+  
+  for (let i=left; i <= right; i++) { // left부터 right까지를 구한다.
+      let row = parseInt(i/n);	// 행(row)을 구한다.
+      let column = i%n;	// 열(column)을 구한다.
+      answer.push(Math.max(row, column) + 1) // 행과 열중 큰 값을 푸시한다.
+  }
+  return answer
+}
\ No newline at end of file
diff --git "a/level-2/\354\265\234\353\214\223\352\260\222\352\263\274-\354\265\234\354\206\237\352\260\222.js" "b/level-2/\354\265\234\353\214\223\352\260\222\352\263\274-\354\265\234\354\206\237\352\260\222.js"
index a8105f7..e16ed19 100644
--- "a/level-2/\354\265\234\353\214\223\352\260\222\352\263\274-\354\265\234\354\206\237\352\260\222.js"
+++ "b/level-2/\354\265\234\353\214\223\352\260\222\352\263\274-\354\265\234\354\206\237\352\260\222.js"
@@ -14,4 +14,13 @@ function solution(s) {
     const arr = s.split(' ').map(x => parseInt(x, 10)).sort((a, b) => a - b)
     answer = arr[0] + ' ' + arr[arr.length - 1]
     return answer;
+}
+
+//정답 3 - jaewon1676
+function solution(s) {
+    s = s.split(' ')
+    s.sort((a, b) => {return a - b}) // 오름차순 정렬
+    let small = s[0] // s의 최솟값
+    let large = s[s.length - 1] // s의 최댓값
+    return (small + ' ' + large)
 }
\ No newline at end of file
diff --git "a/level-2/\354\271\264\355\216\253.js" "b/level-2/\354\271\264\355\216\253.js"
index c81c724..147962f 100644
--- "a/level-2/\354\271\264\355\216\253.js"
+++ "b/level-2/\354\271\264\355\216\253.js"
@@ -12,4 +12,30 @@ function widthHeightPair(size) {
     let result = []
     for (let i = 1; i <= Math.sqrt(size); i++) if (size % i === 0) result.push([size / i, i])
     return result
-}
\ No newline at end of file
+}
+
+//정답 2 - jaewon1676
+function solution(brown, yellow) {
+    var answer = [];
+    let sum = brown + yellow; 
+    
+    //카펫의 최소높이는 3부터이다.(테두리 갈색, 가운데 노란색)
+    for(let height=3; height<brown/2; height++){
+        //전체 크기에서 높이로 나눌때 나머지가 없을경우만 진행
+        if(sum % height === 0){
+            //가로길이
+            let weight = sum / height;
+            //테두리를 제외한 길이를 구해야하기 때문에 각각 -2해준뒤 곱셈 하여 답을 구한다.
+            if( (height-2) * (weight-2) === yellow){
+                return [weight, height];
+            }
+        }
+    }
+    return answer;
+}
+// 완전탐색 
+  
+// 문제 설명에서의 중앙은 노란색, 테두리는 갈색이 포인트입니다.
+// 갈색은 항상 노란색의 가로 세로 크기보다 +2 만큼 큽니다.
+// 따라서 높이는 전체 테두리/2보다 작으므로 
+// 3부터 brown/2 를 순회합니다.
\ No newline at end of file
diff --git "a/level-3/\353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.js" "b/level-3/\353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.js"
new file mode 100644
index 0000000..eb6f1b4
--- /dev/null
+++ "b/level-3/\353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.js"
@@ -0,0 +1,34 @@
+//https://github.com/codeisneverodd/programmers-coding-test
+//완벽한 정답이 아닙니다.
+//정답 1 - jaewon1676
+function solution(routes) {
+  let cctv = 1;  // cctv의 개수는 최소 1개
+  routes.sort((a, b) => a[0] - b[0]); // 고속도로 진입 시점을 기준으로 오름차순 정렬
+  // [ [ -20, -15 ], [ -18, -13 ], [ -14, -5 ], [ -5, -3 ] ]
+  let out = routes[0][1]; // -15
+  // 나간 시점(out)은 첫 차량의 나간시점으로 초기화
+  
+  for(let i = 1; i < routes.length; i++) {
+    // 나간 시점(out)보다 현재 차량의 진입이 느리다면 카메라 추가 설치
+    if(out < routes[i][0]) {
+      cctv++;
+      out = routes[i][1]; // out 시점 업데이트
+    }
+    
+    // 나간 시점(out)이 현재 차량의 진출시점보다 큰 경우 
+    if(out > routes[i][1]) {
+      out = routes[i][1]; // out 시점 업데이트 
+    }
+  }
+  
+  return cctv;
+}
+// 그리디
+
+// 우리는 카메라를 최소로 설치 해야합니다. 그러기 위해서는 고속도로 진입 시점을 기준으로 오름차순 정렬을(빨리 진입한 순) 합니다.
+// 이렇게 되면 배열에 있는 모든 고속도로 진입 시점은 배열의 첫번째 고속도로 진입 시점보다 더 뒤에 있습니다. 그러므로 우리는 
+// 나간시점만 검사 해주면 됩니다.
+
+// 먼저 첫번째 routes의 고속도로를 빠져나간 시점을 out 변수에 담아줍니다.
+// 이 out 변수를 두번째 routes의 고속도로를 빠져나간 시점과 비교하여 out 변수보다 route[i][1]가 크면 ( 나간 시간이 느리면)
+// cctv를 하나 늘려줍니다. , out 변수를 갱신 하며 세번째, 네번째도 계속 비교해줍니다.
\ No newline at end of file