java - 相同的代码为 Java 7 和 8 产生不同的输出

Question

将输入指定为 91912323 时，对于 Java 8，输出为 33221199，而在 Java 7 中，输出为 11223399。

还提供了问题陈述供您引用。

如有任何帮助，我们将不胜感激。

A string consists of digits from 1-9 will be passed as input. The program must print the digits sorted based on the number of occurrence. If one or more digits occur the same number of times, the smallest digit must be printed first.

Input Format: The first line will contain the N digits from 1-9

Boundary Conditions: 3 <= N <= 30

Output Format: The digits sorted based on the number of occurrence.

Example Input/Output 1:

Input: 4443338993

Output: 3333444998

Explanation: 3 occurs the most number of times (four times). Hence it is printed first. 4 occurs thrice and hence printed after the 3s. 9 occurs twice and hence printed after the 4s. 8 occurs only once and hence printed after 9.

Example Input/Output 2:

Input: 95559998228

Output: 99995552288

Explanation: Here 2 and 8 occurs twice. Hence 2 being the smaller digit is printed before 8.

package E001;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

/**
 *
 * @author Anagh
 */

public class CharOccurrences {

    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String input = br.readLine();
        char[] arr = input.toCharArray();
        HashMap<String, Integer> map = new HashMap<>();
        for(int i = 0; i < arr.length; i++)
        {
            if(!map.containsKey(String.valueOf(arr[i])))
            {
                map.put(String.valueOf(arr[i]), 1);
            }
            else
            {
                map.put(String.valueOf(arr[i]), map.get(String.valueOf(arr[i]))+1);
            }
        }
        TreeMap<String, Integer> output = sortByValue(map);
        printMap(output);

    }
    public static TreeMap<String, Integer> sortByValue (HashMap<String, Integer> map) 
    {
    ValueComparator vc =  new ValueComparator(map);
    TreeMap<String,Integer> sortedMap = new TreeMap<>(vc);
    sortedMap.putAll(map);
    return sortedMap;
    }

    private static void printMap(TreeMap<String, Integer> map) {
        String key;
        int value;
        for (Map.Entry<String, Integer> entry : map.entrySet()) 
        {
            key = entry.getKey();
            value = entry.getValue();
            for(int j = 0; j < value; j++)
            {
                System.out.print(key);
            }
    }        
    }

}
class ValueComparator implements Comparator<String> {

    Map<String, Integer> map;

    public ValueComparator(Map<String, Integer> base) {
        this.map = base;
    } 
    @Override
    public int compare(String a, String b) {
        if (map.get(a) > map.get(b)) {
            return -1;
        } else {
            return 1;
        } // returning 0 would merge keys 
    }
}

Answer 1

Output: 99995552288

Explanation: Here 2 and 8 occurs twice. Hence 2 being the smaller digit is printed before 8.

您的比较器没有实现该逻辑。为了让它实现该逻辑，它应该是:

public int compare(String a, String b) {
    if (map.get(a) > map.get(b)) {
        return -1;
    } else if (map.get(a) < map.get(b)) {
        return 1;
    } else {
        return a.compareTo(b);
    }
}