HDU 1686 Oulipo

#include <iostream>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;

char a[1000100];
char b[10100];
int Len_a, Len_b, sum;
int Next[10100];

void GetNext()
{
    int i = 0, j = Next[0] = -1;
    while (i < Len_b)
    {
        if (j == -1 || b[i] == b[j])
        {
            i++;
            j++;
            Next[i] = (b[i] == b[j] ? Next[j] : j);
        }
        else
            j = Next[j];
    }
}

void KMP()
{
    int i = 0, j = 0;
    while (i < Len_a)
    {
        if (j == -1 || a[i] == b[j])
        {
            i++;
            j++;
            if (j == Len_b)
            {
                sum++;
                j = Next[j];
            }
        }
        else
            j = Next[j];
    }
}

int main(void)
{
    ios::sync_with_stdio(false);
    
    int cas;
    cin >> cas;
    while (cas--)
    {
        cin >> b >> a;
        Len_a = strlen(a);
        Len_b = strlen(b);
        GetNext();
        sum = 0;
        KMP();
        cout << sum << endl;
    }
    
    return 0;
}