【manacher】模板

考试竟然写错了manacher！太耻辱了！所以赶快又敲了一遍模板！！一定不能错了aaaa

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;

char a[], M[];
int max_r[], ans;

void manacher ( ) {
    int len = strlen ( a );
    M[] = '@'; M[] = '#';
    for ( int i = ; i < len; i ++ ) {
        M[i*+] = a[i];
        M[i*+] = '#';
    }
    M[len*+] = '$';
    int center = , mx = ;
    for ( int i = ; i <= len *  + ; i ++ ) {
        if ( mx > i ) max_r[i] = min ( mx - i, max_r[center *  - i] );
        else max_r[i] = ;
        while ( M[i + max_r[i]] == M[i - max_r[i]] ) max_r[i] ++;
        if ( mx < i + max_r[i] ) {
            mx = i + max_r[i]; center = i;
        }
        ans = max ( ans, max_r[i] -  );
    }
}

int main ( ) {
    scanf ( "%s", a );
    manacher ( );
    printf ( "%d", ans );
    return ;
}