[SW Expert Academy] 반반 (D3)

https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AXjS1GXqZ8gDFATi&categoryId=AXjS1GXqZ8gDFATi&categoryType=CODE&problemTitle=%EB%B0%98%EB%B0%98&orderBy=FIRST_REG_DATETIME&selectCodeLang=ALL&select-1=&pageSize=10&pageIndex=1&&&&&&&&&

SW Expert Academy

 

 

1. 알파벳을 담을 수 있는 int 배열을 만듦

import java.util.Scanner;

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

		int t = sc.nextInt();

		for (int tc = 1; tc <= t; tc++) {

			int count[] = new int[26];

			String str = sc.next();
			int num = 0;

			for (int i = 0; i < str.length(); i++) {
				count[str.charAt(i) - 'A']++;
			}

			for (int i = 0; i < count.length; i++) {
				if (count[i] == 2 | count[i] != 0)
					num++;
			}

			if (num == 2)
				System.out.println("#" + tc + " Yes");
			else
				System.out.println("#" + tc + " No");

		}
	}
}

 

2. HashMap for에서 Integer value  사용 

import java.util.HashMap;
import java.util.Scanner;

class Solution {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int t = sc.nextInt();
		
		for(int tc=1;tc<=t;tc++) {
		
		String str = sc.next();
			
		HashMap<Character,Integer> map = new HashMap<>();
		
		for(int i=0;i<str.length();i++) {
			map.put(str.charAt(i), map.getOrDefault(str.charAt(i),0)+1);
		}
		
		if(map.size()==2) {
			for( Integer value : map.values()) {
				if(value!=2) {
					System.out.println("#"+tc+" "+"No");
					continue;
				}
			}
			System.out.println("#"+tc+" "+"Yes");
					
		}
		else {
			System.out.println("#"+tc+" "+"No");
		}
		
		
		}
		
	}
}

 

3. HashMap for에서 entry 사용 

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

class Solution {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int t = sc.nextInt();
		
		for(int tc=1;tc<=t;tc++) {
		
		String str = sc.next();
			
		HashMap<Character,Integer> map = new HashMap<>();
		
		for(int i=0;i<str.length();i++) {
			map.put(str.charAt(i), map.getOrDefault(str.charAt(i),0)+1);
		}
		
		if(map.size()==2) {
			for( Map.Entry<Character, Integer> m:map.entrySet()) {
				if(m.getValue()!=2) {
					System.out.println("#"+tc+" "+"No");
					continue;
				}
			}
			System.out.println("#"+tc+" "+"Yes");
					
		}
		else {
			System.out.println("#"+tc+" "+"No");
		}
		
		
		}
		
	}
}

 

4. HashSet 사용

import java.util.HashSet;
import java.util.Scanner;

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

		int t = sc.nextInt();

		for (int tc = 1; tc <= t; tc++) {

			HashSet<Character> set = new HashSet<>();

			// char[] str = sc.next().toCharArray();

			String str = sc.next();

			for (int i = 0; i < str.length(); i++) {
				set.add(str.charAt(i));
			}

			System.out.println("#" + tc + " " + (set.size() == 2 ? "Yes" : "No"));

		}

	}
}

 

AAAB,CDCC와 같은 테스트 케이스가 추가가 안 되어 있어서 이렇게도 풀리는 것 같은데,

문제 요구사항을 따진다면 이 방법은 쓰면 안 될 것 같다.