Sort Letters by Case

Given a string which contains only letters. Sort it by lower case first and upper case second.

Example

For "abAcD", a reasonable answer is "acbAD"

与将负数都放在前面，正数都放在后面的题目一样。

时间复杂度为O（n)

找到第一大写字母，记录其下标为i，则小写字母必定在i之后出现，在i之后找到第一个出现的小写字母j。交换i, j. 注意：i 到 j 之间的字母必定为大写。依次进行即可。

 public class Solution {

     /**

      *@param chars: The letter array you should sort by Case

      *@return: void

      */

     public void sortLetters(char[] chars) {

         if (chars == null || chars.length == 0) {

             return;

         }

         int i = 0;

         for (i = 0; i < chars.length; i++) {

             if (chars[i] >= 'A' && chars[i] <= 'Z') {

                 break;

             }

         }

         for (int j = i + 1; j < chars.length; j++) {

             if (chars[j] >= 'a' && chars[j] <= 'z') {

                 char temp = chars[i];

                 chars[i] = chars[j];

                 chars[j] = temp;

                 i++;

             }

         }

         return;

     }

 }

巴特西

Sort Letters by Case

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