一个排序题目

[seagullbb]

有一数组,如int[] a={2,3,4,3,5,15,44,33,66,3,7,7,9};将数组排序,并输出如下
2 出现次数为:1 次
3 出现次数为:3 次
4 出现次数为:1 次
5 出现次数为:1 次
7 出现次数为:2 次

[youzi530]

顶一.

[wangydong]

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

public class Test {

    public static void main(String[] args) {
        int[] a={2,3,4,3,5,15,44,33,66,3,7,7,9};
        Map<Integer, Integer> m = new HashMap<Integer, Integer>();
        for(int i = 0; i < a.length; i++){
            if(!m.containsKey(a[i])){
                m.put(a[i], 1);
            }else{
                m.put(a[i], m.get(a[i])+1);
            }
        }
    }
}

[xuhaiyang]

hashmap

[良言相告]

这种题不需要用到Map吧

public static void main(String args[]) {
		int[] a = { 2, 3, 4, 3, 5, 15, 44, 33, 66, 3, 7, 7, 9 };
		// sort
		Arrays.sort(a);
		// out
		int currentValue = a[0], count = 0;
		for (int i : a) {
			if (i == currentValue) {
				count++;
			} else {
				System.out.printf("%-3d出现次数为:%-3d\n", currentValue, count);
				currentValue = i;
				count = 1;
			}
		}
	}

[wensheng_zh2007]

对啊，用hashmap会好一些

[良言相告]

单单从本题来讲
用HashMap从哪方面讲都没感觉到好处

[老紫竹]

http://www.java2000.net/p9635
参考这个，

[invoke100]

import java.util.*;

public class Statistics{
public static void main(String args[]) {
int[] a = {2,3,4,3,5,15,44,33,66,3,7,7,9};
Arrays.sort(a);
Map<Integer, Integer> m = new TreeMap<Integer, Integer>();
for(int i = 0; i < a.length; i++) {
int item = a[i];
Integer freq = m.get(item);
m.put(item, freq == null ? 1: freq + 1);
}
Print(m);
}

static void Print(Map m) {
Iterator it = m.entrySet().iterator();
while(it.hasNext()) {
Map.Entry e = (Map.Entry)it.next();
System.out.println(e.getKey() + "出现次数为:::" + e.getValue() + "次");
}
}
}

[zhanggc1001]

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

public class Test {

	public static void main(String[] args) {
		int[] a={2,3,4,3,5,15,44,33,66,3,7,7,9};
		Map<Integer, Integer> m = new HashMap<Integer, Integer>();
		for(int i = 0; i < a.length; i++){
			if(!m.containsKey(a[i])){
				m.put(a[i], 1);
			}else{
				m.put(a[i], m.get(a[i])+1);
			}
		}
	}
}