b1rc challenge by @jeevjyot (#551)

* b1rc challenge

* fixed a rounding error

* added the file back

* fixed file

* removed a file

---------

Co-authored-by: Jeevjyot Singh Chhabda <jeevjyotsinghchhabda@Jeevjyots-MBP.hsd1.ca.comcast.net>

1 files changed, 107 insertions, 0 deletions

diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_jeevjyot.java b/src/main/java/dev/morling/onebrc/CalculateAverage_jeevjyot.java
new file mode 100644
index 0000000..191e407
--- /dev/null
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage_jeevjyot.java
@@ -0,0 +1,107 @@
+/*
+ *  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 static java.lang.Math.round;
+import static java.util.stream.Collectors.*;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collector;
+
+public class CalculateAverage_jeevjyot {
+
+    public static final String MEAUREMENT_FILE = "./measurements.txt";
+
+    public static void main(String[] args) throws IOException {
+        Map<String, tempMeasurement> result = new ConcurrentHashMap<>();
+        Files.lines(Path.of(MEAUREMENT_FILE))
+                .parallel()
+                .forEach(s -> {
+                    var separatorIndex = s.indexOf(";");
+                    var stationName = s.substring(0, separatorIndex);
+                    var temp = s.substring(separatorIndex + 1);
+                    result.computeIfAbsent(stationName, d -> new tempMeasurement(parseDoubleFast(temp)))
+                            .recordTemp(parseDoubleFast(temp));
+                });
+
+        TreeMap<String, tempMeasurement> sortedStats = new TreeMap<>(result);
+        System.out.println(sortedStats);
+    }
+
+    public static double parseDoubleFast(String str) {
+        // Simple implementation - can be improved with more error checking and support for different formats
+        boolean negative = false;
+        double result = 0;
+        int length = str.length();
+        int i = 0;
+        if (str.charAt(0) == '-') {
+            negative = true;
+            i++;
+        }
+        for (; i < length; i++) {
+            char c = str.charAt(i);
+            if (c == '.') {
+                int divisor = 1;
+                for (i++; i < length; i++) {
+                    result += (double) (str.charAt(i) - '0') / (divisor *= 10);
+                }
+                break;
+            }
+            result = result * 10 + (c - '0');
+        }
+        return negative ? -result : result;
+    }
+
+    private static double round(double value) {
+        return Math.round(value * 10.0) / 10.0;
+    }
+
+    public static class tempMeasurement {
+        double minTemp;
+        double maxTemp;
+        double sum;
+        int count;
+
+        public tempMeasurement(double temString) {
+            this.minTemp = temString;
+            this.maxTemp = temString;
+            this.sum = 0.0;
+            this.count = 0;
+        }
+
+        public synchronized void recordTemp(Double temp) {
+            this.minTemp = Math.min(minTemp, temp);
+            this.maxTemp = Math.max(maxTemp, temp);
+            sum += temp;
+            count++;
+        }
+
+        double getAverage() {
+            return round(sum) / count;
+        }
+
+        @Override
+        public String toString() {
+            return String.format("%.1f/%.1f/%.1f", round(minTemp), round(getAverage()), round(maxTemp));
+        }
+    }
+}