LintCode 1784: Decrease To Be Palindrome

本文已参与「新人创作礼」活动，一起开启掘金创作之路。

原文链接：blog.csdn.net/roufoo/arti…

Decrease To Be Palindrome Given a string s with a-z. We want to change s into a palindrome with following operations:

change ‘z’ to ‘y’; change ‘y’ to ‘x’; change ‘x’ to ‘w’; … change ‘c’ to ‘b’; change ‘b’ to ‘a’; Returns the number of operations needed to change s to a palindrome at least. Example Example 1:

Input: “abc” Output: 2 Explanation:

Change ‘c’ to ‘b’: “abb” Change the last ‘b’ to ‘a’: “aba” Example 2: Input: “abcd” Output: 4

解法1： 代码如下：

class Solution {
public:
    /**
     * @param s: the string s
     * @return: the number of operations at least
     */
    int numberOfOperations(string &s) {
        int n = s.size();
        if (n <= 1) return 0;
        
        int count = 0;
        int i = 0, j = n - 1;
        while(i < j) {
            if (s[i] != s[j]) count += abs(s[j] - s[i]);
            i++;
            j--;
        }
        
        return count;
    }
};