验证回文字符串II

示例 1:
输入: "aba"
输出: True

示例 2:
输入: "abca"
输出: True
解释: 你可以删除c字符。

class Solution {
public:
    bool checkPalindrome(const string& s, int low, int high) {
        for (int i = low, j = high; i < j; ++i, --j) {
            if (s[i] != s[j]) {
                return false;
            }
        }
        return true;
    }
    bool validPalindrome(string s) {
        int low = 0, high = s.size() - 1;
        while (low < high) {
            char c1 = s[low], c2 = s[high];
            if (c1 == c2) {
                ++low;
                --high;
            }
            else {
                return checkPalindrome(s, low, high - 1) || checkPalindrome(s, low + 1, high);
            }
        }
        return true;
    }
};