개발생각

덧칠하기 : 연습문제 Lv.1

https://school.programmers.co.kr/learn/courses/30/lessons/161989

def solution(n, m, section):
    answer = 0
    
    while section:
        paint = section[0]
        
        while section and section[0] < paint+ m:
            section.pop(0)
        answer+=1
    
    return answer

완주하지 못한 선수: 해시 Lv.1

https://school.programmers.co.kr/learn/courses/30/lessons/42576

import java.util.HashMap;

class Solution {
    public String solution(String[] participant, String[] completion) {
        String answer = "";
        
       	HashMap<String, Integer> map = new HashMap<>();
		
		for(int i=0, l=participant.length;i<l;i++) {
			String key = participant[i];
			map.put(key, map.getOrDefault(key, 0)+1);
		}
		
		for(int i=0, l=completion.length;i<l;i++) {
			String key = completion[i];
			map.replace(key, map.get(key)-1);
		}
		
		return map.entrySet().stream().filter(e->e.getValue()==1).findFirst().get().getKey();
    }
}

둘만의 암호: 연습 문제 Lv.1

https://school.programmers.co.kr/learn/courses/30/lessons/155652

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

class Solution {
    public String solution(String s, String skip, int index) {
        String answer = "";

		char[] word = s.toCharArray();
		for(int i=0;i<word.length;i++) {
			for(int j=0;j<index;j++) {				
				do {
					word[i]++;
					if(word[i] >'z') word[i] -= 26;
					
//					System.out.println(j);
//					System.out.println(word[i]);
				}while(skip.contains(String.valueOf(word[i])));
			}
		}
		
		answer = String.valueOf(word);
        
        return answer;
    }
}

게임 맵 최단거리: 깊이/너비 우선 탐색(DFS/BFS) Lv.2

https://school.programmers.co.kr/learn/courses/30/lessons/1844

import java.util.LinkedList;
import java.util.Queue;

class Solution {
    public int solution(int[][] maps) {
        int[][] visit = new int[maps.length][maps[0].length];
        
		Queue<GameMapLoc> q = new LinkedList<>();
		q.add(new GameMapLoc(0,0,0));
		
		while(q.size() > 0) {
			int x = q.peek().x;
			int y = q.peek().y;
			int answer = q.poll().moveCnt;
			
			if(x == maps.length-1 && y == maps[0].length-1) {
				return answer + 1;
			}
			
			int[] xx = {-1, 0, 1, 0};
			int[] yy = {0, -1, 0, 1};
			
			for(int i=0;i<4;i++) {
				int ax = x+xx[i];
				int ay = y+yy[i];
				
				if(ax>=0 && ay>=0 && ax<maps.length && ay<maps[0].length) {
					if(maps[ax][ay] == 1 && visit[ax][ay] == 0) {
                        visit[ax][ay] = 1;
						q.add(new GameMapLoc(ax, ay, answer+1));
					}					
				}
			}
		}
        
        return -1;
    }
}

class GameMapLoc{
	int x;
	int y;
	int moveCnt;
	
	public GameMapLoc(int x, int y, int moveCnt) {
		// TODO Auto-generated constructor stub
		this.x = x;
		this.y = y;
		this.moveCnt = moveCnt;
	}
}

JadenCase 문자열 만들기: 연습문제 Lv.2

https://school.programmers.co.kr/learn/courses/30/lessons/12951

class Solution {
    public String solution(String s) {
        String answer = "";
        
		for(int i=0;i<s.length();i++) {
			if(i>0) {
				if(s.charAt(i-1) == ' ' && ((s.charAt(i) > 96 && s.charAt(i) < 123) || (s.charAt(i) > 64 && s.charAt(i) < 91))) {
					answer += String.valueOf(Character.toUpperCase(s.charAt(i)));
				} else {
					answer += String.valueOf(Character.toLowerCase(s.charAt(i)));
				}
			}else {
				answer += String.valueOf(Character.toUpperCase(s.charAt(i)));
			}
		}
        
        return answer;
    }
}