leetcode557. Reverse Words in a String III

557. Reverse Words in a String III

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:Input: "Let's take LeetCode contest"Output: "s'teL ekat edoCteeL tsetnoc"

解法

先转为字符串数组，没遇到一个空格，将前一个空格和现在的空格之间的字符串反转一次。因为最后一个单词结尾不会有空格，所以单独再反转一次。

public class Solution {    public String reverseWords(String s) {        if (s == null || s.length() == 0) {            return "";        }        char[] charArray = s.toCharArray();        int i = 0;        for (int j = 0; j < charArray.length; j++) {            if (charArray[j] == ' ') {                reverse(charArray, i, j - 1);                i = j + 1;            }        }        reverse(charArray, i, charArray.length - 1);        return new String(charArray);    }    public void reverse(char[] s, int left, int right) {        while (left < right) {            char temp = s[left];            s[left] = s[right];            s[right] = temp;            left++;            right--;        }    }}