package com.kingdz.algorithm.time201707;
/**
* <pre>
* 字符链条
*
* http://judgecode.com/problems/1010
*
* Little Tom wants to change all the words into palindromes.
* To do this, he follows 2 rules:
* (a) He can reduce the value of a letter, e.g. he can change 'd' to 'c', but he cannot change 'c' to 'd'.
* (b) In order to form a palindrome, if he has to repeatedly reduce the value of a letter, he can do it until the letter becomes 'a'.
* Once a letter has been changed to 'a', it can no longer be changed.
* Each reduction in the value of any letter is counted as a single operation.
* Find the minimum number of operations required to convert a given string into a palindrome.
*
* </pre>
*
* @author kingdz
*
*/
public class Algo10 {
public static void main(String[] args) {
String input = "aba";
int ret = getMinChange(input);
System.out.println("min change:" + ret);
}
private static int getMinChange(String input) {
int count = 0;
int length = input.length();
// 将两侧的字符依次比较，以较小的字符为准，如果a和c比较，将c变成a即可，只需要改变2次
for (int i = 0; i < length / 2; i++) {
char a = input.charAt(i);
char b = input.charAt(length - i - 1);
count = count + Math.abs((int) a - (int) b);
}
return count;
}
}
