字符串旋轉

題目：Reverse String （難度一顆星）

Write a function that takes a string as input and returns the string reversed.
Example:
Given s = "hello", return "olleh".

實現：

 1 class Solution {  2 public:  3     string reverseString(string s) {  4         int length = s.length();  5         int start = 0;  6         int ends = length - 1;  7         while(start < ends)  8  {  9             int temp = s[start]; 10             s[start] = s[ends]; 11             s[ends] = temp; 12             start++; 13             ends--; 14  } 15         return s; 16  } 17 };

 

題目：Reverse Vowels of a String （難度一顆星）

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:
Given s = "hello", return "holle".

Example 2:
Given s = "leetcode", return "leotcede".

 

實現：

 1 class Solution {  2 public:  3     bool validate(char c)  4  {  5         return (c == 'a') || (c == 'e') || (c == 'i') || (c == 'o') || (c == 'u') || (c == 'A') || (c == 'E') || (c == 'I') || (c == 'O') || (c == 'U');  6  }  7     
 8     string reverseVowels(string s) {  9         int starts = 0; 10         int ends = s.size()-1; 11         while (starts < ends) 12  { 13             while (!validate(s[starts])) 14  { 15                 starts++; 16  } 17             while (!validate(s[ends])) 18  { 19                 ends--; 20  } 21             if (starts > ends) 22  { 23                 break; 24  } 25             int temp = s[starts]; 26             s[starts] = s[ends]; 27             s[ends] = temp; 28             starts++; 29             ends--; 30  } 31         return s; 32 } 33 };