string matching

http://acm.hdu.edu.cn/showproblem.php?pid=6629 

#include <iostream>
#include <cstring>
#include <queue>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <set>
#include <map>
#include <stack>
#include <ctime>
//#include <tr1/unordered_map>
//#include <unordered_map>
#include <cmath>
//#include<bits/stdc++.h>
using namespace std;

#define sfi(i) scanf("%d",&i)
#define sfl(i) scanf("%I64d",&i)
#define sfs(i) scanf("%s",(i))
#define pri(i) printf("%d\n",i)
#define prl(i) printf("%I64d\n",i)
#define sff(i) scanf("%lf",&i)
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define mem(x,y) memset(x,y,sizeof(x))
#define INF 0x3f3f3f3f
#define inf 8e19
#define eps 1e-10
#define PI acos(-1.0)
#define lowbit(x) ((x)&(-x))
#define fl() printf("flag\n")
#define MOD(x) ((x%mod)+mod)%mod
#define endl '\n'
#define pb push_back
#define lson (rt<<1)
#define rson (rt<<1|1)
//#define pii pair<int,int>
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)

template<typename T>inline void read(T &x)
{
    x=0;
    static int p;p=1;
    static char c;c=getchar();
    while(!isdigit(c)){if(c=='-')p=-1;c=getchar();}
    while(isdigit(c)) {x=(x<<1)+(x<<3)+(c-48);c=getchar();}
    x*=p;
}

//-----------------------------------------------
const int maxn=1e6+9;
const int maxm=1e6;
const int mod=1e9+7;

int nex[maxn];
int extend[maxn];
void getnext(char str[])
{
    int i=0,j,pos,len=strlen(str);
    nex[0]=len;
    while(str[i]==str[i+1]&&i+1<len) i++;
    nex[1]=i;
    pos=1;
    for(int i=2;i<len;i++)
    {
        if(nex[i-pos]+i<nex[pos]+pos)
            nex[i]=nex[i-pos];
        else
        {
            j=nex[pos]+pos-i;
            if(j<0) j=0;
            while(i+j<len&&str[j]==str[j+i]) j++;
            nex[i]=j;
            pos=i;
        }
    }
}

void EXKMP(char s1[],char s2[])
{
    int i=0,j,pos,len=strlen(s1),len2=strlen(s2);
    getnext(s2);
    while(s1[i]==s2[i]&&i<len2&&i<len) i++;
    extend[0]=i;
    pos=0;
    for(int i=1;i<len;i++)
    {
        if(nex[i-pos]+i<extend[pos]+pos)
            extend[i]=nex[i-pos];
        else
        {
            j=extend[pos]+pos-i;
            if(j<0) j=0;
            while(i+j<len&&j<len2&&s1[j+i]==s2[j]) j++;
            extend[i]=j;
            pos=i;
        }
    }
}

char s1[maxn],s2[maxn];
int main()
{
    //FAST_IO;

    //freopen("input.txt","r",stdin);


    int T;
    sfi(T);
    while(T--)
    {
        scanf("%s",s1);
        strcpy(s2,s1);

        EXKMP(s1,s2);

        int n=strlen(s1);

        ll ans=0;
        for(int i=1;i<n;i++)
        {
            //cout<<extend[i]<<endl;
            if(extend[i]==n-i)
            {
                ans+=extend[i];
            }
            else ans+=extend[i]+1;
        }

        printf("%lld\n",ans);

    }


    return 0;
}