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1 /*
2 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，
3 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
4 */
5 /************************************************
6 * Author :Running_Time
7 * Created Time :2015-8-5 14:04:26
8 * File Name :HDOJ_1711.cpp
9 ************************************************/
10
11 #include <cstdio>
12 #include <algorithm>
13 #include <iostream>
14 #include <sstream>
15 #include <cstring>
16 #include <cmath>
17 #include <string>
18 #include <vector>
19 #include <queue>
20 #include <deque>
21 #include <stack>
22 #include <list>
23 #include <map>
24 #include <set>
25 #include <bitset>
26 #include <cstdlib>
27 #include <ctime>
28 using namespace std;
29
30 #define lson l, mid, rt << 1
31 #define rson mid + 1, r, rt << 1 | 1
32 typedef unsigned long long ull;
33 typedef long long ll;
34 const int MAXN = 1e6 + 10;
35 const int MAXM = 1e4 + 10;
36 const int INF = 0x3f3f3f3f;
37 const ull KEY = 100000007;
38 int a[MAXN], b[MAXM];
39 int n, m;
40
41 int match(void) {
42 ull h = 1;
43 for (int i=0; i<m; ++i) h *= KEY;
44 ull ah = 0, bh = 0;
45 for (int i=0; i<m; ++i) ah = ah * KEY + a[i];
46 for (int i=0; i<m; ++i) bh = bh * KEY + b[i];
47 for (int i=0; i+m<=n; ++i) {
48 if (ah == bh) return i + 1;
49 if (i + m < n) {
50 ah = ah * KEY + a[i+m] - a[i] * h;
51 }
52 }
53 return -1;
54 }
55
56 int main(void) { //HDOJ 1711 Number Sequence
57 int T; scanf ("%d", &T);
58 while (T--) {
59 scanf ("%d%d", &n, &m);
60 for (int i=0; i<n; ++i) scanf ("%d", &a[i]);
61 for (int i=0; i<m; ++i) scanf ("%d", &b[i]);
62 printf ("%d\n", match ());
63 }
64
65 return 0;
66 }
1 /* 2 题目链接：http://oj.acm.zstu.edu.cn/JudgeOnline/problem.php?id=4194 3 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。 4 */ 5 /************************************************ 6 * Author :Running_Time 7 * Created Time :2015-8-5 14:04:26 8 * File Name :ZSTU 4194 字符串匹配 9 ************************************************/ 10 11 #include <cstdio> 12 #include <algorithm> 13 #include <iostream> 14 #include <sstream> 15 #include <cstring> 16 #include <cmath> 17 #include <string> 18 #include <vector> 19 #include <queue> 20 #include <deque> 21 #include <stack> 22 #include <list> 23 #include <map> 24 #include <set> 25 #include <bitset> 26 #include <cstdlib> 27 #include <ctime> 28 using namespace std; 29 30 #define lson l, mid, rt << 1 31 #define rson mid + 1, r, rt << 1 | 1 32 typedef unsigned long long ull; 33 typedef long long ll; 34 const int MAXN = 1e6 + 10; 35 const int INF = 0x3f3f3f3f; 36 const ull KEY = 100000007; 37 char t[MAXN], p[MAXN]; 38 39 int Rabin_Karp(void) { 40 int lent = strlen (t); 41 int lenp = strlen (p); 42 ull h = 1; 43 for (int i=0; i<lenp; ++i) h *= KEY; 44 ull th = 0, ph = 0; int ret = 0; 45 for (int i=0; i<lenp; ++i) th = th * KEY + t[i]; 46 for (int i=0; i<lenp; ++i) ph = ph * KEY + p[i]; 47 for (int i=0; i+lenp<=lent; ++i) { 48 if (th == ph) { 49 ret++; 50 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 51 th = th * KEY + t[j+lenp] - t[j] * h; 52 } 53 i += lenp - 1; continue; 54 } 55 if (i + lenp < lent) { 56 th = th * KEY + t[i+lenp] - t[i] * h; 57 } 58 } 59 return ret; 60 } 61 62 int main(void) { //ZSTU 4194 字符串匹配 63 while (scanf ("%s %s", t, p) == 2) { 64 printf ("%d\n", Rabin_Karp ()); 65 } 66 67 return 0; 68 }
Rabin_Karp(hash) HDOJ 1711 Number Sequence
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原文地址：http://www.cnblogs.com/Running-Time/p/4705115.html
