order
This article mainly records leetcode Reverse the vowels in a string
subject
Write a function , String as input , Invert the vowels in the string .
Example 1：
Input ："hello"
Output ："holle"
Example 2：
Input ："leetcode"
Output ："leotcede"
Tips ：
Vowels do not contain letters "y" .
source ： Power button （LeetCode）
link ：https://leetcode-cn.com/problems/reverse-vowels-of-a-string
Copyright belongs to the network . For commercial reprint, please contact the official authority , Non-commercial reprint please indicate the source .Answer key
class Solution {
Set<Character> set = new HashSet(){{
add('a');
add('e');
add('i');
add('o');
add('u');
add('A');
add('E');
add('I');
add('O');
add('U');
}};
public String reverseVowels(String s) {
int i = 0;
int j = s.length() - 1;
char[] chars = s.toCharArray();
while(i < j) {
while (!set.contains(chars[i]) && i<j) {
i++;
}
while (!set.contains(chars[j]) && i<j) {
j--;
}
if (i < j) {
char tmp = chars[i];
chars[i] = chars[j];
chars[j] = tmp;
i++;
j--;
}
}
return new String(chars);
}
}Summary
So let's use this HashSet Storing vowels in uppercase and lowercase , After that, we use the head and tail pointer to traverse the string array at the same time , When i The characters pointed to and j When all the characters pointed to are vowels , Exchange and update the pointer at the same time , Only update the pointer when it is not a vowel character .
