HDU6135 拓展KMP模板

emmm...模板,虽然每太搞懂

#include <iostream>
#include <cstdio>
#include <string.h>
#pragma warning ( disable : 4996 )
using namespace std;

inline int Max(int a,int b) { return a>b?a:b; }
inline int Min(int a,int b) { return a>b?b:a; }
const int inf = 0x3f3f3f3f;
const int maxn = 1e6+5;

char str[maxn], nstr[maxn];
int nex[maxn], extend[maxn];
int len, nlen;
long long ans, mod = 1000000007;

void init()
{
    ans = 0;
    memset( str, 0, sizeof(str) );
    memset( nstr, 0, sizeof(nstr) );

    scanf( "%s", str );  len = strlen(str);   reverse(str, str+len);
    scanf( "%s", nstr ); nlen = strlen(nstr); reverse(nstr, nstr+nlen);
}

void getNext()
{
    nex[0] = nlen;
    int po, far;        //po表示目前匹配的起始点，far表示最远点

    for (int i = 1, j = -1; i < nlen; i++, j-- )
    {
        if ( j < 0 || i + nex[i-po] >= far )
        {
            if(j<0) { far=i;j++; }
            while(far<nlen&&nstr[far]==nstr[j])
            { far++; j++; }

            nex[i] = j;
            po = i;
        }
        else
            nex[i] = nex[i-po];
    }
}

void getExtend()
{
    int po, far;

    for ( int i = 0, j = -1; i < len; i++, j-- )
    {
        if ( j < 0 || i + nex[i-po] >= far )
        {
            if(j<0) { far=i;j++; }
            while(far<len && j<nlen && str[far]==nstr[j] )
            { far++; j++; }

            extend[i] = j;
            po = i;
        }
        else
            extend[i] = nex[i-po];
    }
}

int main()
{
    int all; cin >> all;
    while (all--)
    {
        init();
        getNext();
        getExtend();

        long long tmp;
        for ( int i = 0; i < len; i++ )
        {
            tmp = (long long)extend[i];
            ans = ( ans + tmp*(tmp+1)/2 ) % mod;
        }
        printf( "%lld\n", ans );
    }
    return 0;
}