问Java中的数组处理(两列)

EN

public static void main (String[] args) throws java.lang.Exception
{
        String S = "5,a\n" +
           "6,b\n" +
           "9,a";

        String[] lines = S.split("\\n");
        Map<String, Integer> map = new HashMap<String, Integer>();
        for( String t : lines )
        {
            String[] e = t.split(",");
            Integer digit = Integer.parseInt(e[0]);
            String c = e[1];
            if ( map.get(c) != null )
            {
                Integer val = map.get(c);
                val += digit;
                map.put( c, val );
            }
            else
            {
                map.put( c, digit );
            }

        }

        int max = 0;
        String maxKey = null;
        for ( String k : map.keySet() )
        {
            if ( map.get(k) > max )
            {

                max = map.get(k);
                maxKey = k;
            }
        }

        System.out.println("The maximum key is : " + maxKey );
        System.out.println("The maximum value is : " + max );
    }

The maximum key is : a
The maximum value is : 14

import java.util.HashMap;
import java.util.Map;

public class ParseTest {

    public static void main(String[] args) {
        String S = "5,a\n" + "6,b\n" + "9,a";

        String maxKey = null;
        int maxVal = 0;

        Map<String, Integer> sums = new HashMap<>();
        for (String a : S.split("\\n")) {
            String[] split = a.split(",");
            int value = Integer.parseInt(split[0]);
            String key = split[1];

            if (sums.containsKey(key)) {
                sums.put(key, sums.get(key) + value);
            } else {
                sums.put(key, value);
            }

            if (sums.get(key) > maxVal) {
                maxVal = sums.get(key);
                maxKey = key;
            }
        }

        System.out.println("Max key: " + maxKey + ", Sum: " + maxVal);
    }
}

public static void main(String[] args) {
    String S = "5,a\n6,b\n9,a";
    Map<String, Integer> map = new HashMap<String, Integer>();
    String highestAmountChar = "";
    int highestAmount = 0;
    for (String str : S.split("\\n")) {
        String[] amountChar = str.split(",");
        if (map.get(amountChar[1]) == null) {
            map.put(amountChar[1], Integer.parseInt(amountChar[0]));
        } else {
            map.put(amountChar[1], map.get(amountChar[1]) + Integer.parseInt(amountChar[0]));
        }
        if (highestAmount < map.get(amountChar[1])) {
            highestAmount = map.get(amountChar[1]);
            highestAmountChar = amountChar[1];
        }
    }

    System.out.println("The character " + highestAmountChar + " has highest amount " + highestAmount);
}