C# 代码
public class Solution {
public string MakeSmallestPalindrome(string s) {
int n = s.Length;
char[] ch = s.ToCharArray();
int left = 0, right = n - 1;
while (left < right){
if (ch[left] != ch[right]){
char min = (char)Math.Min(ch[left], ch[right]);
ch[left] = min;
ch[right] = min;
}
left++;
right--;
}
return new string(ch);
}
}