TIL

IT. Programming

TIL

Zpoxic 2021. 11. 8. 13:47

1. 직사각형 별 찍기

//개인 솔루션

import java.util.Scanner;

class Solution {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();

for(int i=0 ; i<b ; i++){
for(int j=0; j<a ; j++){
System.out.print("*");
}
System.out.println();
}
}
}

//공부해볼 코드

import java.util.Scanner;
import java.util.stream.IntStream;

public class Solution {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();

StringBuilder sb = new StringBuilder();
IntStream.range(0, a).forEach(s -> sb.append("*"));
IntStream.range(0, b).forEach(s -> System.out.println(sb.toString()));
}
}

2. 짝수와 홀수

//개인 솔루션

class Solution {
public String solution(int num) {
String answer = "";
if(num%2==0){
answer="Even";
}
else{
answer="Odd";
}
return answer;
}
}

//공부할 코드 (삼항연산자)

public class EvenOrOdd {
String evenOrOdd(int num) {
return num % 2 == 0 ? "Even": "Odd";
}

public static void main(String[] args) {
//String str = "1 2 3 4";
EvenOrOdd evenOrOdd = new EvenOrOdd();
//아래는 테스트로 출력해 보기 위한 코드입니다.
System.out.println("결과 : " + evenOrOdd.evenOrOdd(3));
System.out.println("결과 : " + evenOrOdd.evenOrOdd(2));
}
}

4. 두 정수 사이의 합

//개인 솔루션

class Solution {
public long solution(int a, int b) {
long answer = 0;

if(a>b){
for(long i=b;i<=a;i++){
answer += i;
}
}

else if(a<b){
for (long i=a;i<=b;i++){
answer += i;
}
}

else{
answer = a;
}
return answer;
}
}

//공부해볼 코드 (등차수열의 합 공식)

class Solution {

public long solution(int a, int b) {
return sumAtoB(Math.min(a, b), Math.max(b, a));
}

private long sumAtoB(long a, long b) {
return (b - a + 1) * (a + b) / 2;
}
}

5. 문자열을 정수로 바꾸기

Java String > Int형태로 바꾸는 함수

https://wotres.tistory.com/entry/Java-String%EC%9D%84-int%EB%A1%9C-%EB%B3%80%ED%99%98%ED%95%98%EB%8A%94-%EB%B2%95

//개인 솔루션

class Solution {
public int solution(String s) {
int answer = 0;
answer = Integer.parseInt(s);
return answer;
}
}

6. 없는 숫자 더하기

//개인 솔루션

class Solution {
public int solution(int[] numbers) {
int answer = 0;

for(int sum=0 ; sum<=9 ; sum++){
answer += sum;
}

for(int index=0 ; index < numbers.length ; index++){
answer -= numbers[index];
}

return answer;
}
}

//공부해볼 코드 (함수 이용)

import java.util.Arrays;
import java.util.stream.IntStream;

class Solution {
public int solution(int[] numbers) {
return IntStream.range(0, 10).filter(i -> Arrays.stream(numbers).noneMatch(num -> i == num)).sum();
}
}

//공부해볼 코드2 (삼항연산자)

class Solution {
public int solution(int[] numbers) {
var map = new int[10];

for (int v : numbers) map[v] = 1;

int sum = 0;
for (int v = 0; v < map.length; v++) sum += (map[v] == 0) ? v : 0;

return sum;
}
}

8. 평균 구하기

//개인 솔루션

class Solution {
public double solution(int[] arr) {
double answer = 0;
double sum = 0;

for (int i=0 ; i<arr.length ; i++){
sum += arr[i];
answer = sum/arr.length;
}

return answer;
}
}

9. 핸드폰 번호 가리기

class Solution {
public String solution(String phone_number) {
String answer = "";
char[] secretpn = new char[phone_number.length()];

for(int i=0 ; i<phone_number.length() ; i++){
if ( phone_number.length()-4 <= i){
secretpn[i] = phone_number.toCharArray()[i];
answer += secretpn[i];
}
else {
secretpn[i] = '*';
answer += secretpn[i];
}

}
return answer;
}
}

10. 행렬의 덧셈

class Solution {
public int[][] solution(int[][] arr1, int[][] arr2) {
int[][] answer = arr1;

for(int i=0 ; i<arr1.length ; i++){
for(int j=0 ; j<arr1[i].length ; j++){
answer[i][j] = arr1[i][j] + arr2[i][j];
}
}
return answer;
}
}

12. 부족한 금액 계산하기

//한줄매직..

class Solution {
public long solution(long price, long money, long count) {
return Math.max(price * (count * (count + 1) / 2) - money, 0);
}
}

13. 2016년

//JAVA 코드

class Solution {
public String solution(int a, int b) {
String answer = "";
int[] month = {31,28,31,30,31,30,31,31,30,31,30,31};
String[] week = {"FRI","SAT","SUN","MON","TUE","WED","THU"};
int days=0;

int year = 2016;
if(year%4==0){
month[1]=month[1]+1;
}

if( a<13 && b <32) {
for(int i=1 ; i<a ; i++){
days += month[i-1];
}
days += b-1;

answer = week[days%7];
}
return answer;
}
}

public class Main {
public static void main(String[] args) {
Solution sol = new Solution();

int month = 5;
int day = 24;

String result = sol.solution(month,day);

System.out.println(result);
}
}