Rabin_Karp(hash) HDOJ 1711 Number Sequence

题目传送门

/*
　　Rabin_Karp：虽说用KMP更好，但是RK算法好理解。简单说一下RK算法的原理：首先把模式串的哈希值算出来，
        在文本串里不断更新模式串的长度的哈希值，若相等，则找到了，否则整个模式串的长度的哈希值向右移动一位
*/
/************************************************
* Author        :Running_Time
* Created Time  :2015-8-5 14:04:26
* File Name     :HDOJ_1711.cpp
 ************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef unsigned long long ull;
typedef long long ll;
const int MAXN = 1e6 + 10;
const int MAXM = 1e4 + 10;
const int INF = 0x3f3f3f3f;
const ull KEY = 100000007;
int a[MAXN], b[MAXM];
int n, m;

int match(void) {
    ull h = 1;
    for (int i=0; i<m; ++i)    h *= KEY;
    ull ah = 0, bh = 0;
    for (int i=0; i<m; ++i)    ah = ah * KEY + a[i];
    for (int i=0; i<m; ++i)    bh = bh * KEY + b[i];
    for (int i=0; i+m<=n; ++i)    {
        if (ah == bh)   return i + 1;
        if (i + m < n) {
            ah = ah * KEY + a[i+m] - a[i] * h;
        }
    }
    return -1;
}

int main(void)    {     //HDOJ 1711 Number Sequence
    int T;  scanf ("%d", &T);
    while (T--) {
        scanf ("%d%d", &n, &m);
        for (int i=0; i<n; ++i)    scanf ("%d", &a[i]);
        for (int i=0; i<m; ++i)    scanf ("%d", &b[i]);
        printf ("%d
", match ());
    }

    return 0;
}

/*
    题目链接：http://oj.acm.zstu.edu.cn/JudgeOnline/problem.php?id=4194
    给你两个字符串A，B，请输出B字符串在A字符串中出现了几次。
*/
/************************************************
 * Author        :Running_Time
 * Created Time  :2015-8-5 14:04:26
 * File Name     :ZSTU 4194 字符串匹配
 ************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef unsigned long long ull;
typedef long long ll;
const int MAXN = 1e6 + 10;
const int INF = 0x3f3f3f3f;
const ull KEY = 100000007;
char t[MAXN], p[MAXN];

int Rabin_Karp(void) {
    int lent = strlen (t);
    int lenp = strlen (p);
    ull h = 1;
    for (int i=0; i<lenp; ++i)    h *= KEY;
    ull th = 0, ph = 0; int ret = 0;
    for (int i=0; i<lenp; ++i)    th = th * KEY + t[i];
    for (int i=0; i<lenp; ++i)    ph = ph * KEY + p[i];
    for (int i=0; i+lenp<=lent; ++i)    {
        if (th == ph)   {
            ret++;
            for (int j=i; j<=i+lenp-1; ++j) {       //找到了一个模式串，不能再用，整个跳过去
                th = th * KEY + t[j+lenp] - t[j] * h;
            }
            i += lenp - 1;  continue;
        }
        if (i + lenp < lent) {
            th = th * KEY + t[i+lenp] - t[i] * h;
        }
    }
    return ret;
}

int main(void)    {     //ZSTU 4194 字符串匹配
    while (scanf ("%s %s", t, p) == 2)  {
        printf ("%d
", Rabin_Karp ());
    }

    return 0;
}

/*
    这就是赤裸裸的模板题，只不过用数字而已
*/
/************************************************
* Author        :Running_Time
* Created Time  :2015-8-9 19:45:40
* File Name     :KMP.cpp
 ************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int MAXN = 1e6 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
int nex[MAXN];
int s[MAXN], t[MAXN];

void get_nex(int lm)    {
    int i = 0, j = -1;   nex[0] = -1;
    while (i < lm)  {
        if (j == -1 || t[j] == t[i]) {
            i++;    j++;    nex[i] = j;
        }
        else    j = nex[j];
    }
}

int KMP(int ln, int lm)   {
    get_nex (lm);
    int i = 0, j = 0;
    while (i < ln)  {
        while (j != -1 && s[i] != t[j]) j = nex[j];
        i++;    j++;
        if (j == lm) return (i - j + 1);
    }
    return -1;
}

int main(void)    {     //HDOJ 1711 Number Sequence
    int T;  scanf ("%d", &T);
    while (T--)   {
        int ln, lm; scanf ("%d%d", &ln, &lm);
        for (int i=0; i<ln; ++i)   scanf ("%d", &s[i]);
        for (int i=0; i<lm; ++i)   scanf ("%d", &t[i]);
        printf ("%d
", KMP (ln, lm));
    }

    return 0;
}