# HDU 3336 Count the string (基础KMP）

It is well known that AekdyCoin is good at string problems as well as number theory problems. When given a string s, we can write down all the non-empty prefixes of this string. For example:
s: "abab"

The prefixes are: "a", "ab", "aba", "abab"

For each prefix, we can count the times it matches in s. So we can
see that prefix "a" matches twice, "ab" matches twice too, "aba" matches
once, and "abab" matches once. Now you are asked to calculate the sum
of the match times for all the prefixes. For "abab", it is 2 + 2 + 1 + 1
= 6.

The answer may be very large, so output the answer mod 10007.

InputThe first line is a single integer T, indicating the number of test cases.

For each case, the first line is an integer n (1 <= n <=
200000), which is the length of string s. A line follows giving the
string s. The characters in the strings are all lower-case letters.

OutputFor each case, output only one number: the sum of the match times for all the prefixes of s mod 10007.Sample Input

```1
4
abab```

Sample Output

```6

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

const int N = 1000002;
int Next[N];
char S[N], T[N];
int slen, tlen;//注意每次一定要计算长度
const int MOD=1e4+7;
void getNext()
{
int j, k;
j = 0; k = -1; Next = -1;
while(j < tlen)
if(k == -1 || T[j] == T[k])
Next[++j] = ++k;
else
k = Next[k];

}
int main()
{
int t;
scanf("%d",&t);
while(t--)
{
scanf("%d",&tlen);
scanf("%s",T);
getNext();
int ans=tlen%MOD;
for(int i=2;i<=tlen;i++){
if(Next[i]>0)
ans=(ans+1)%MOD;
}
printf("%d\n",ans);
}
return 0;
}```

## hdu 3336 Count the string【kmp】

http://acm.hdu.edu.cn/showproblem.php?pid=3336 题意:给你一个字符串,问字符串每一个前缀在字符串中的出现总次数. 思路:kmp的应用,自身和自身进行匹配,每次匹配时,如果没有匹配到结束,模式串按next数组向后移动,出现匹配至结束的情况,匹配串往后移动一位 ,匹配过程中,出现失配时,统计当前已经匹配的字符个数,累加到总数中,直到匹配串移动到最后一位. 其实前两天就在网上看题解用kmp+dp的方法来写了这道题,然而后来细思一些细节,自己并没有弄懂,所以

## HDU - 3336 Count the string (扩展kmp)

It is well known that AekdyCoin is good at string problems as well as number theory problems. When given a string s, we can write down all the non-empty prefixes of this string. For example: s: "abab" The prefixes are: "a", "ab&qu

## hdu 3336 Count the string

Count the stringTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4239    Accepted Submission(s): 1977 Problem Description It is well known that AekdyCoin is good at string problems as well as num

## KMP——hdu 3336 count the string

Count the string Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 10478    Accepted Submission(s): 4893 Problem Description It is well known that AekdyCoin is good at string problems as well as n

## hdu 3336 Count the string KMP+DP

Count the string Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 6375    Accepted Submission(s): 2947 Problem Description It is well known that AekdyCoin is good at string problems as well as n