개발생각

카펫 : 완전 탐색 Lv2

https://school.programmers.co.kr/learn/courses/30/lessons/42842

class Solution {
    public int[] solution(int brown, int yellow) {
        int[] answer = new int[2];
        
        int w = (brown + yellow) / 3; //가로 최대 길이 = 전체 격자 개수 / 3
		int h = 3; //세로 최소 길이 = 3
		
		while(w >= h) {
			if(w*h == brown + yellow && 2*(w + h) == (brown + 4)) {
				answer[0] = w;
				answer[1] = h;
				break;
			}
			h++;
			w = (brown + yellow) / h;
		}
        
        return answer;
    }
}

타겟 넘버 : 깊이/너비 우선 탐색(DFS/BFS) Lv2

https://school.programmers.co.kr/learn/courses/30/lessons/43165

class Solution {
    int answer = 0;
    
    public int solution(int[] numbers, int target) {
        getDFS(numbers, 0, target, 0);
        return answer;
    }
    
    public void getDFS(int[] numbers, int depth, int target, int sum) {
		if(depth == numbers.length) {
			if(target == sum) answer++; 
		} else {
			getDFS(numbers, depth + 1, target, sum + numbers[depth]);
			getDFS(numbers, depth + 1, target, sum - numbers[depth]);
		}
	}
}

구명보트 : 탐욕법(Greedy) Lv.2

https://school.programmers.co.kr/learn/courses/30/lessons/42885

import java.util.Arrays;

class Solution {
    public int solution(int[] people, int limit) {
        int answer = 0;
        
        // TODO Auto-generated method stub
		//int[] people = {10,20,70,80,90};
		//int limit = 100;
		//int boat=0;
		
		int idx = 0;
		Arrays.sort(people);
		
		for(int i= people.length-1; i >= idx; i--) {
			if(people[idx] + people[i] <=limit) {
				idx++;
			}
			
			answer++;
		}
		
		//System.out.println(boat);
        
        return answer;
    }
}

연습문제 : 햄버거 만들기 Lv.1

https://school.programmers.co.kr/learn/courses/30/lessons/133502

import java.util.Stack;

class Solution {
    public int solution(int[] ingredient) {
        int answer = 0;
        Stack<Integer> s = new Stack<Integer>();

        for (int idx : ingredient) {
            s.push(idx);

            if (s.size() >= 4) {
                if (s.get(s.size() - 1) == 1 && s.get(s.size() - 2) == 3 && s.get(s.size() - 3) == 2 && s.get(s.size() - 4) == 1) {
                    answer++;
                    s.pop();
                    s.pop();
                    s.pop();
                    s.pop();
                }
            }
        }
        
        return answer;
    }
}

2019 카카오 개발자 겨울 인턴십 : 크레인 인형뽑기 게임 Lv.1

https://school.programmers.co.kr/learn/courses/30/lessons/64061

import java.util.*;

class Solution {
    public int solution(int[][] board, int[] moves) {
        int answer = 0;
        Stack<Integer> stack = new Stack<>();
        
        for(int i=0;i<moves.length;i++){
            int moveIdx = moves[i] - 1;
            
            for(int j=0;j<board.length;j++){
                int k = board[j][moveIdx];
            
                if(k == 0) continue;
                if(!stack.empty() && stack.peek() == k){
                    stack.pop();
                    answer += 2;
                } else {
                    stack.push(k);
                }
                
                board[j][moveIdx] = 0;
                break;
            }
        }
        
        return answer;
    }
}