Add: algorithm of baekjoon

Author: ImSejin

src/main/java/io/github/imsejin/study/baekjoon/silver/P18110.java

@@ -0,0 +1,49 @@
+package io.github.imsejin.study.baekjoon.silver;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+public class P18110 {
+
+    public static void main(String[] args) throws Exception {
+        try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
+            int[] difficulties = new int[Integer.parseInt(reader.readLine())];
+
+            for (int i = 0; i < difficulties.length; i++) {
+                int difficulty = Integer.parseInt(reader.readLine());
+                difficulties[i] = difficulty;
+            }
+
+            int answer = solve(difficulties);
+            System.out.println(answer);
+        }
+    }
+
+    static int solve(int[] difficulties) {
+        if (difficulties.length == 0) return 0;
+
+        final int excluded = -1;
+        Arrays.sort(difficulties);
+        int excludedCount = (int) Math.round(difficulties.length * 0.15);
+
+        for (int i = 0; i < excludedCount; i++) {
+            difficulties[i] = excluded;
+            difficulties[difficulties.length - 1 - i] = excluded;
+        }
+
+        int sum = 0;
+        int count = 0;
+        for (int difficulty : difficulties) {
+            if (difficulty == excluded) {
+                continue;
+            }
+
+            sum += difficulty;
+            count++;
+        }
+
+        return (int) Math.round((double) sum / count);
+    }
+
+}

src/test/groovy/io/github/imsejin/study/baekjoon/silver/P18110Spec.groovy

@@ -0,0 +1,20 @@
+package io.github.imsejin.study.baekjoon.silver
+
+import spock.lang.Specification
+
+class P18110Spec extends Specification {
+
+    def "test"() {
+        when:
+        def actual = P18110.solve(difficulties as int[])
+
+        then:
+        actual == expected
+
+        where:
+        difficulties                           | expected
+        [1, 5, 5, 7, 8]                        | 6
+        [1, 13, 12, 15, 3, 16, 13, 12, 14, 15] | 13
+    }
+
+}