Mihahim has a string s. He wants to delete exactly one character from it so that the resulting string would be a palindrome. Determine if he can do it, and if he can, what character should be deleted.
Input
The input contains a string s of length (2 ≤ |s| ≤ 200000), consisting of lowercase Latin letters.
Output
If the solution exists, output «YES» (without quotes) in the first line. Then in the second line output a single integer x — the number of the character that should be removed from s so that the resulting string would be a palindrome. The characters in the string are numbered from 1. If there are several possible solutions, output any of them.
If the solution doesn‘t exist, output «NO» (without quotes).
Examples
input
evertree
output
YES2
input
emerald
output
NO
input
aa
output
YES2
从左右两边往中间移动，如果相同，l++，r--，如果不同，第一次循环i==0时，则让l++，第二次循环则让r--，最后判断不同的出现了几次。如果dif是0，l>=r代表本身就是回文，则去掉l位置的字符。
#include <cstring>
#include <cstdio>
#define N 100005
char s[N<<1];
int len,l,r,dif,at;
int main() {
scanf("%s",s);
len=strlen(s);
for(int i=0;i<2;i++){
dif=0;
l=0,r=len-1;
while(l<r){
if(s[l]!=s[r]){
dif++;
if(i){
at=r;
r--;
}else {
at=l;
l++;
}
}
if(s[l]==s[r]){
l++;
r--;
}
}
if(l>=r&&dif==0)at=l;
if(dif<2){
printf("YES\n%d\n",at+1);
break;
}
}
if(dif>1)puts("NO");
}