Codeforces Beta Round #7 D. Palindrome Degree —— 字符串哈希

题目链接：http://codeforces.com/contest/7/problem/D

D. Palindrome Degree

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

String s of length n is called k-palindrome, if it is a palindrome itself, and its prefix and suffix of length  are (k - 1)-palindromes. By definition, any string (even empty) is 0-palindrome.

Let's call the palindrome degree of string s such a maximum number k, for which s is k-palindrome. For example, "abaaba" has degree equals to 3.

You are given a string. Your task is to find the sum of the palindrome degrees of all its prefixes.

Input

The first line of the input data contains a non-empty string, consisting of Latin letters and digits. The length of the string does not exceed 5·106. The string is case-sensitive.

Output

Output the only number — the sum of the polindrome degrees of all the string's prefixes.

Examples

input

a2A

output

1

input

abacaba

output

6

代码如下：

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const double eps = 1e-6;
const int INF = 2e9;
const LL LNF = 9e18;
const int mod = 1e9+7;
const int maxn = 5e6+10;

char s[maxn];
int dp[maxn];

int main()
{
    scanf("%s",s+1);
    int l = 0, r = 0, m = 1;
    for(int i = 1; s[i]; i++)
    {
        l = l*137+s[i];
        r = r+s[i]*m, m *= 137;
        if(l==r)
            dp[i] = dp[i/2]+1;
    }

    int ans = 0;
    for(int i = 1; s[i]; i++)
        ans += dp[i];
    printf("%d
",ans);
}