Day76

알고리즘 코드카타

Average Selling Price

with production as( 
    select a.product_id, b.units, a.price, (b.units * a.price) as summary
    from Prices a
    left join UnitsSold b
    on a.product_id = b.product_id
    where b.purchase_date between a.start_date and a.end_date
)

select a.product_id, ifnull(round(sum(b.summary)/sum(b.units), 2), 0) as average_price 
from Prices a
left join production b
on a.product_id = b.product_id
group by a.product_id
;

숫자 짝꿍

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

class Solution {
    public String solution(String X, String Y) {
        String answer = "";

        char[] xs = X.toCharArray();
        char[] ys = Y.toCharArray();

        List<Character> list = new ArrayList<>();

        for(char xi : xs){
            for (int i = 0; i < ys.length; i++) {
                if (ys[i] == ' ') {
                    continue;
                }

                if (ys[i] == xi) {
                    list.add(xi);
                    ys[i] = ' ';
                    break;
                }
            }
        }

        list.sort(Comparator.reverseOrder());
        if(list.isEmpty()){
            return "-1";
        } else if (list.get(0) == '0') {
            return "0";
        } else {
            for (char c : list){
                answer += c;
            }
            return answer;
        }
    }
}

런타임 에러발생으로 아래처럼 수정

import java.util.*;


class Solution {
    public String solution(String X, String Y) {
        StringBuilder answerBuilder = new StringBuilder();

        char[] xs = X.toCharArray();
        char[] ys = Y.toCharArray();

        Arrays.sort(xs);
        Arrays.sort(ys);

        // 두 배열의 끝에서부터 비교
        int xPtr = xs.length - 1;
        int yPtr = ys.length - 1;

        while (xPtr >= 0 && yPtr >= 0) {
            if (xs[xPtr] > ys[yPtr]) {
                xPtr--; // X의 숫자가 더 크면 X 포인터만 이동
            } else if (xs[xPtr] < ys[yPtr]) {
                yPtr--; // Y의 숫자가 더 크면 Y 포인터만 이동
            } else { // 두 숫자가 같으면 짝꿍이므로 결과에 추가
                answerBuilder.append(xs[xPtr]);
                xPtr--;
                yPtr--;
            }
        }

        String answer = answerBuilder.toString();

        if (answer.isEmpty()) {
            return "-1";
        } else if (answer.startsWith("0")) {
            return "0";
        } else {
            return answer;
        }
    }
}