POJ 3461 Oulipo (裸KMP)

传送门

给出模式串和文本串，求模式串在文本串中共匹配几次。

套板子上就完了。
 

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cmath>
#include <string>
#include <vector>
#include <stack>
#include <map>
#include <sstream>
#include <cstring>
#include <set>
#include <cctype>
#include <bitset>
#define IO                       \
    ios::sync_with_stdio(false); \
    // cin.tie(0);                  \
    // cout.tie(0);
using namespace std;
typedef long long LL;
const int maxn = 1e7 + 100;
const int maxm = 1e6 + 10;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int inf = 0x3f3f3f3f;
const LL mod = 1e9 + 7;
const double pi = acos(-1);
int dis[8][2] = {0, 1, 1, 0, 0, -1, -1, 0, 1, -1, 1, 1, -1, 1, -1, -1};
string p, t;
int nextp[maxn];
void Get_nextp(int n)
{
    for (int i = 1; i < n; i++)
    {
        int j = i;
        while (j > 0)
        {
            j = nextp[j];
            if (p[i] == p[j])
            {
                nextp[i + 1] = j + 1;
                break;
            }
        }
    }
}

int Kmp(int lenp, int lent)
{
    int i, j;
    int ans = 0;
    for (i = 0, j = 0; i < lent; i++)
    {
        if (j < lenp && t[i] == p[j])
            j++;
        else
        {
            while (j > 0)
            {
                j = nextp[j];
                if (t[i] == p[j])
                {
                    j++;
                    break;
                }
            }
        }
        if (j == lenp)
            ans++;
    }
    return ans;
}
int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
#endif
    IO;
    int T;
    cin >> T;
    while (T--)
    {
        cin >> p >> t;
        memset(nextp, 0, sizeof nextp);
        Get_nextp(p.size());
        cout << Kmp(p.size(), t.size()) << "\n";
    }
    return 0;
}