Add yehwankim23 (#148)

1 files changed, 105 insertions, 0 deletions

diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_yehwankim23.java b/src/main/java/dev/morling/onebrc/CalculateAverage_yehwankim23.java
new file mode 100644
index 0000000..53878cd
--- /dev/null
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage_yehwankim23.java
@@ -0,0 +1,105 @@
+/*
+ *  Copyright 2023 The original authors
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package dev.morling.onebrc;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileReader;
+import java.io.OutputStreamWriter;
+import java.util.HashMap;
+import java.util.TreeMap;
+
+public class CalculateAverage_yehwankim23 {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new FileReader("./measurements.txt"));
+        HashMap<String, Measurement> hm = new HashMap<>();
+        char[] buffer = new char[107];
+        int offset = 0;
+
+        while (true) {
+            br.read(buffer, offset, 107 - offset);
+            int semicolon = 0;
+
+            while (buffer[semicolon] != ';') {
+                semicolon++;
+            }
+
+            String stationName = new String(buffer, 0, semicolon++);
+            int newline = semicolon;
+
+            while (buffer[newline] != '\n') {
+                newline++;
+            }
+
+            if (hm.containsKey(stationName)) {
+                hm.get(stationName).update(Double.parseDouble(
+                        new String(buffer, semicolon, newline - semicolon)));
+            }
+            else {
+                hm.put(stationName, new Measurement(
+                        Double.parseDouble(new String(buffer, semicolon, newline - semicolon))));
+            }
+
+            if (buffer[++newline] == 0) {
+                break;
+            }
+
+            offset = 107 - newline;
+            char[] temp = new char[107];
+            System.arraycopy(buffer, newline, temp, 0, offset);
+            buffer = temp;
+        }
+
+        br.close();
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        bw.write(new TreeMap<>(hm).toString());
+        bw.newLine();
+        bw.flush();
+        bw.close();
+    }
+
+    private static class Measurement {
+        public double min;
+        public double sum;
+        public int count;
+        public double max;
+
+        public Measurement(double measurement) {
+            min = measurement;
+            sum = measurement;
+            count = 1;
+            max = measurement;
+        }
+
+        public void update(double measurement) {
+            if (measurement < min) {
+                min = measurement;
+            }
+
+            sum += measurement;
+            count++;
+
+            if (max < measurement) {
+                max = measurement;
+            }
+        }
+
+        @Override
+        public String toString() {
+            return min + "/" + Math.round(sum / count * 10) / 10.0 + "/" + max;
+        }
+    }
+}