A. Mike and palindrome
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
Mike has a string s consisting of only lowercase English letters. He wants to change exactly onecharacter from the string so that the resulting one is a palindrome.
A palindrome is a string that reads the same backward as forward, for example strings "z", "aaa", "aba", "abccba" are palindromes, but strings "codeforces", "reality", "ab" are not.
Input
The first and single line contains string s (1 ≤ |s| ≤ 15).
Output
Print "YES" (without quotes) if Mike can change exactly one character so that the resulting string is palindrome or "NO" (without quotes) otherwise.
Examples
input
abccaa
output
YES
input
abbcca
output
NO
input
abcda
output
YES
【代码】：
#include <bits/stdc++.h>
using namespace std;
int cnt=0;
char a[30];
int main()
{
scanf("%s",a);
int n=strlen(a);
for(int i=0;i<n/2;i++)//注意！回文串只要判长度一半
{
if(a[i]!=a[n-i-1])
cnt++;
}
//cout<<cnt<<endl;
if(((n%2)&&(cnt==0))||cnt==1) puts("YES");//注意特判
else puts("NO");
return 0;
}