Feature/delf nov3

src/delf/etc/ln/Ln02.java

@@ -0,0 +1,38 @@
+package etc.ln;
+
+/**
+ * @author delf
+ */
+public class Ln02 {
+	public static void main(String[] args) {
+		System.out.println(new Ln02().solution("4132315142", new String[]{"3241523133", "4121314445", "3243523133", "4433325251", "2412313253"}));
+		System.out.println(new Ln02().solution("53241", new String[]{"53241", "42133", "53241", "14354"}));
+		System.out.println(new Ln02().solution("24551", new String[]{"24553", "24553", "24553", "24553"}));
+	}
+
+	public int solution(String answerSheet, String[] sheet) {
+		int maxCheatProbabilityIndex = 0;
+		for (int p1 = 0; p1 < sheet.length - 1; p1++) {
+			for (int p2 = p1 + 1; p2 < sheet.length; p2++) {
+				// p1과 p2의 '부정행위 가능성 지수' 계산
+				int totalDoubtCount = 0;
+				int longestDoubtCount = 0;
+				int doubtCount = 0;
+				for (int q = 0; q < answerSheet.length(); q++) {
+					if (sheet[p1].charAt(q) == sheet[p2].charAt(q) && sheet[p1].charAt(q) != answerSheet.charAt(q)) {
+						doubtCount++;
+						totalDoubtCount++;
+					} else {
+						doubtCount = 0;
+					}
+					longestDoubtCount = Math.max(longestDoubtCount, doubtCount);
+				}
+				// 최댓값 기록
+				int cheatProbabilityIndex = totalDoubtCount + (int) Math.pow(longestDoubtCount, 2);
+				maxCheatProbabilityIndex = Math.max(maxCheatProbabilityIndex, cheatProbabilityIndex);
+			}
+		}
+
+		return maxCheatProbabilityIndex;
+	}
+}

src/delf/programmers/Solution42747.java

@@ -0,0 +1,30 @@
+package programmers;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * H-index
+ * https://programmers.co.kr/learn/courses/30/lessons/42747
+ */
+public class Solution42747 {
+
+	public static void main(String[] args) {
+		System.out.println(new Solution42747().solution(new int[]{1, 3, 0, 6, 5}));
+		System.out.println(new Solution42747().solution(new int[]{135, 778, 512, 923, 111, 344}));
+	}
+
+	/*
+     * 정렬된 배열 내에서는 h번째 논문은 무조건 h회 이상 인용됨
+     * '그 차이'가 가장 적어질 때가 정답
+	 * */
+	public int solution(int[] citations) {
+		int[] arr = Arrays.stream(citations).boxed().sorted(Comparator.reverseOrder()).mapToInt(i -> i).toArray();
+		for (int h = 0; h < arr.length; h++) {
+			if (arr[h] <= h) {
+				return h;
+			}
+		}
+		return citations.length;
+	}
+}