Sort Letters by Case

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

java

public class Solution {    /*     * @param chars: The letter array you should sort by Case     * @return: nothing     */    public void sortLetters(char[] chars) {        // write your code here        if (chars == null || chars.length == 0 || chars.length == 1) {            return;        }        int left = 0;        int right = chars.length - 1;        while (left <= right) {            while (left <= right && chars[left] >= 'a' && chars[left] <= 'z') {                left++;            }            while (left <= right && chars[right] >= 'A' && chars[right] <= 'Z') {                right--;            }            if (left <= right) {                char temp = chars[left];                chars[left] = chars[right];                chars[right] = temp;                left++;                right--;            }        }    }}

python

class Solution:    """    @param: chars: The letter array you should sort by Case    @return: nothing    """    def sortLetters(self, chars):        # write your code here        if chars is None or len(chars) == 0 or len(chars) == 1:            return        left, right = 0, len(chars) - 1        while left <= right:            while left <= right and chars[left].islower():                left += 1            while left <= right and chars[right].isupper():                right -= 1            if left <= right:                chars[left], chars[right] = chars[right], chars[left]                left += 1                right -= 1