题解 | #字符串排序#
字符串排序
https://www.nowcoder.com/practice/5190a1db6f4f4ddb92fd9c365c944584
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
public class Main{
public static void main(String[] args) throws IOException{
Scanner sc = new Scanner(System.in);
String str = sc.next();
List<Character> letters = new ArrayList<>();
for(char ch: str.toCharArray()){
if (Character.isLetter(ch)) {
letters.add(ch);
}
}
letters.sort(new Comparator<Character>() {
public int compare(Character o1, Character o2) {
return Character.toLowerCase(o1) - Character.toLowerCase(o2);
}
});
StringBuffer sb = new StringBuffer();
int j = 0;
for(int i = 0; i < str.length(); i++){
if(Character.isLetter(str.charAt(i))){
sb.append(letters.get(j++));
}
else{
sb.append(str.charAt(i));
}
}
System.out.println(sb.toString());
}
}
核心点：
1.判断是否为字母
Character.isLetter()2.将字母大写转为小写
Character.toLowerCase(o1)3.
Comparator是稳定的排序，即如果return 0，不会改变两个字母的顺序
