这是一种开始的方法，可以基于以下想法：对映射中初始数组中每个整数发生的次数进行计数。计算完所有数字后，请按升序对地图进行排序，然后打印地图的输出：
import java.util.ArrayList;import java.util.HashMap;import java.util.TreeMap;public class SortCount { public static void main(String[] args) { int nums[] = {0,0,0,1,3,3,2,1,3,5,6,0}; HashMap<Integer,Integer> counts = new HashMap<Integer,Integer>(); for(int i = 0; i < nums.length; i++) { if(counts.containsKey(nums[ Integer c = counts.get(nums[i]) + 1; counts.put(nums[i], c); } else { counts.put(nums[i],1); } } ValueComparator<Integer,Integer> bvc = new ValueComparator<Integer,Integer>(counts); TreeMap<Integer,Integer> sortedMap = new TreeMap<Integer,Integer>(bvc); sortedMap.putAll(counts); ArrayList<Integer> output = new ArrayList<Integer>(); for(Integer i : sortedMap.keySet()) { for(int c = 0; c < sortedMap.get(i); c++) { output.add(i); } } System.out.println(output.toString()); }}它使用一个
Comparator类来比较中的值
Map：
import java.util.Comparator;import java.util.Map;public class ValueComparator<T1,T2 extends Comparable<T2>> implements Comparator<T1> { Map<T1,T2> base; public ValueComparator(Map<T1,T2> base) { this.base = base; } @Override public int compare(T1 k1, T1 k2) { T2 val1 = base.get(k1); T2 val2 = base.get(k2); return val1.compareTo(val2); }}
