若干面试题目

String[] strs = "A@B@C@D".split("@");

import java.util.*;
public class Test{
public static void main(String[] args) {
//System.out.println(countBits(-1));
System.out.println(sortString("SDsBEaA"));
}
//排序方法    public static String sortString(String str){
Character[] characters=new Character[str.length()];
char[] strchars=str.toCharArray();
int count=0;
for(char c:strchars){
characters[count++]=c;
}
//采用匿名类的方式重写比较方法类

Arrays.sort(characters,new Comparator<Character>(){
public int compare(Character c1,Character c2){
if(c1.equals(c2))return 0;
if(Character.toLowerCase(c1)==Character.toLowerCase(c2)){
return c1-c2;
}else{
return Character.toLowerCase(c1)-Character.toLowerCase(c2);
}
}
public boolean equals(Object o){
return true;
}
});
count=0;
for(Character c: characters){
strchars[count++]=c;
}
return new String(strchars);

}
}

<table width="30%" border="0" bgcolor="#000000">
<tr>
<td colspan="4" bgcolor="#FFFFFF">1</td>
</tr>
<tr>
<td rowspan="4" bgcolor="#FFFFFF">2</td>
<td colspan="3" bgcolor="#FFFFFF">3</td>
</tr>
<tr>
<td rowspan="3" bgcolor="#FFFFFF">4</td>
<td colspan="2" bgcolor="#FFFFFF">5</td>
</tr>
<tr>
<td rowspan="2" bgcolor="#FFFFFF">6</td>
<td bgcolor="#FFFFFF">7</td>
</tr>
<tr>
<td bgcolor="#FFFFFF">8</td>
</tr>
</table>

public static void main(String[] args) {
Map<String,Long> charTimesMap = new HashMap<String,Long>();

String str = "hello wolrd wlllkcdfdfdfdfdfdfdfdsfhksadfl,,,,,,,,,,,,,,,,,,,,,s?sdfls  fjs";
str = str.replaceAll("[^a-zA-Z]", "");
//以字符为key，以出现次数为value存入Map中
for (char each : str.toCharArray()) {

String charStr = String.valueOf(each);
if (charTimesMap.containsKey(charStr)) {
Long num = charTimesMap.get(charStr).longValue() + 1;
charTimesMap.put(charStr, num);
} else {
charTimesMap.put(charStr, 1L);
}
}

String maxAppearChar = null;
Long maxAppearTimes = 0L;
//遍历map，entrySet()方法取得map集合
for (Map.Entry<String, Long> charAppear : charTimesMap.entrySet()) {
if (charAppear.getValue() > maxAppearTimes) {
maxAppearChar = charAppear.getKey();
maxAppearTimes = charAppear.getValue();
}
}
System.out.println("出现最多的字母："+maxAppearChar);
System.out.println("出现次数:"+maxAppearTimes);
}