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  1. import java.util.*;
  2. class WeatherRecord {
  3.     String year;
  4.     float temperature;
  5.  
  6.     WeatherRecord(String year, float temperature) {
  7.         this.year = year;
  8.         this.temperature = temperature;
  9.     }
  10. }
  11.  
  12. class Mapper {
  13.     List<WeatherRecord> map(String[] lines) {
  14.         List<WeatherRecord> mappedData = new ArrayList<>();
  15.         for (String line : lines) {
  16.             if (!line.startsWith("Date")) {
  17.                 String[] parts = line.split(",");
  18.                 String year = parts[4];
  19.                 float temp = Float.parseFloat(parts[1]);
  20.                 mappedData.add(new WeatherRecord(year, temp));
  21.             }
  22.         }
  23.         return mappedData;
  24.     }
  25. }
  26.  
  27. class Reducer {
  28.     Map<String, Float> reduce(List<WeatherRecord> mappedData) {
  29.         Map<String, Float> maxTemps = new HashMap<>();
  30.         for (WeatherRecord record : mappedData) {
  31.             maxTemps.put(record.year, Math.max(maxTemps.getOrDefault(record.year, Float.MIN_VALUE), record.temperature));
  32.         }
  33.         return maxTemps;
  34.     }
  35. }
  36.  
  37. public class Main {
  38.     public static void main(String[] args) {
  39.         String[] inputData = {
  40.             "Date,Temperature,Humidity,Wind,Year",
  41.             "2021-04-10,35.2,45,12,2021",
  42.             "2021-04-11,36.1,50,10,2021",
  43.             "2022-04-12,37.8,48,11,2022",
  44.             "2022-05-01,38.3,52,10,2022",
  45.             "2023-04-10,33.2,47,13,2023"
  46.         };
  47.  
  48.         Mapper mapper = new Mapper();
  49.         List<WeatherRecord> mapped = mapper.map(inputData);
  50.  
  51.         Reducer reducer = new Reducer();
  52.         Map<String, Float> results = reducer.reduce(mapped);
  53.  
  54.         for (Map.Entry<String, Float> entry : results.entrySet()) {
  55.             System.out.println("Year: " + entry.getKey() + ", Max Temp: " + entry.getValue());
  56.         }
  57.     }
  58. }
Success #stdin #stdout 0.15s 55776KB
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Year: 2023, Max Temp: 33.2
Year: 2022, Max Temp: 38.3
Year: 2021, Max Temp: 36.1
https://ideone.com/iXVg82
language:
Java (HotSpot 12)
created:
3 days ago
visibility:
public

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