Day58

코드카타 - 알고리즘

H-Index

import java.util.*;

class Solution {
    public int solution(int[] citations) {
        int max = Arrays.stream(citations).max().getAsInt();
        List<Integer> list = new ArrayList<>();

        for (int i = 0; i <= max; i++) {
            int finalI = i;
            int count = Math.toIntExact(Arrays.stream(citations).filter(value -> value >= finalI).count());
            if (count >= i) {
                list.add(i);
            }
        }

        return list.stream().max(Comparator.naturalOrder()).get();
    }
}

3진법 뒤집기

import java.util.*;

class Solution {
    public int solution(int n) {
        String count = Integer.toString(n,3);
        StringBuffer sb = new StringBuffer(count);
        String reverse = sb.reverse().toString();

        return Integer.parseInt(reverse,3);
    }
}

• 진수변환
  • 10진수 -> n진수 : Integer.toString(number,n)
  • n진수 -> 10진수 : Integer.parseInt(string,n)