Description
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"
Note: In the string, each word is separated by single space and there will not be any extra space in the string.
Solution
class Solution {
public String reverseWords(String s) {
int i = 0;
int n = s.length();
char[] arr = s.toCharArray();
while (i < n) {
// skip spaces
while (i < n && arr[i] == ' ') {
++i;
}
int wordStart = i;
// find the end of current word
while (i < n && arr[i] != ' ') {
++i;
}
reverse(arr, wordStart, i - 1);
}
return new String(arr);
}
public void reverse(char[] chars, int start, int end) {
while (start < end) {
swap(chars, start++, end--);
}
}
public void swap(char[] chars, int i, int j) {
char tmp = chars[i];
chars[i] = chars[j];
chars[j] = tmp;
}
}
