2697. 字典序最小回文串 - 力扣(LeetCode)
class Solution {
public:string makeSmallestPalindrome(string s) {int left=0;int right=s.size()-1;while(left<right){if(s[left]<s[right])s[right]=s[left];else if(s[left]>s[right])s[left]=s[right];left++;right--;}return s;}
};