【KMP】POJ-3461 Oulipo

Oulipo

Time Limit: 1000MS Memory Limit: 65536K   

Description

The French author Georges Perec (1936–1982) once wrote a book, La disparition, without the letter 'e'. He was a member of the Oulipo group. A quote from the book:

Tout avait Pair normal, mais tout s’affirmait faux. Tout avait Fair normal, d’abord, puis surgissait l’inhumain, l’affolant. Il aurait voulu savoir où s’articulait l’association qui l’unissait au roman : stir son tapis, assaillant à tout instant son imagination, l’intuition d’un tabou, la vision d’un mal obscur, d’un quoi vacant, d’un non-dit : la vision, l’avision d’un oubli commandant tout, où s’abolissait la raison : tout avait l’air normal mais…

Perec would probably have scored high (or rather, low) in the following contest. People are asked to write a perhaps even meaningful text on some subject with as few occurrences of a given “word” as possible. Our task is to provide the jury with a program that counts these occurrences, in order to obtain a ranking of the competitors. These competitors often write very long texts with nonsense meaning; a sequence of 500,000 consecutive 'T's is not unusual. And they never use spaces.

So we want to quickly find out how often a word, i.e., a given string, occurs in a text. More formally: given the alphabet {'A', 'B', 'C', …, 'Z'} and two finite strings over that alphabet, a word W and a text T, count the number of occurrences of W in T. All the consecutive characters of W must exactly match consecutive characters of T. Occurrences may overlap.

Input

The first line of the input file contains a single number: the number of test cases to follow. Each test case has the following format:

• One line with the word W, a string over {'A', 'B', 'C', …, 'Z'}, with 1 ≤ |W| ≤ 10,000 (here |W| denotes the length of the string W).
• One line with the text T, a string over {'A', 'B', 'C', …, 'Z'}, with |W| ≤ |T| ≤ 1,000,000.

Output

For every test case in the input file, the output should contain a single number, on a single line: the number of occurrences of the word W in the text T.

Sample Input

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

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题意：给出一个模板串和文本，统计文本中该模板出现了多少次。

思路：KMP的模板题。

代码如下：

/* * ID: j.sure.1 * PROG: * LANG: C++ */#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <ctime>#include <cmath>#include <stack>#include <queue>#include <vector>#include <map>#include <set>#include <string>#include <climits>#include <iostream>#define Mem(f, x) memset(f, x, sizeof(f))#define PB push_back#define LL long longusing namespace std;const int INF = 0x3f3f3f3f;const double eps = 1e-8;/****************************************/const int N = 1e6+5, M = 1e4+5;char t[N], p[M];int n, m, f[M];void get_f(){    int i = 0, j = -1;    f[0] = -1;    while(i < m) {        if(j == -1 || p[i] == p[j]) {            i++; j++;            f[i] = j;        }        else j = f[j];    }}int match(){    get_f();    int i = 0, j = 0, ans = 0;    while(i < n) {        if(j == -1 || t[i] == p[j]) {            i++; j++;            if(j == m) {                ans++;                j = f[j];            }        }        else j = f[j];    }    return ans;}int main(){#ifdef J_Sure    //freopen("000.in", "r", stdin);    //freopen("999.out", "w", stdout);#endif    int T;    scanf("%d", &T);    while(T--) {        scanf("%s%s", p, t);        Mem(f, 0);        n = strlen(t); m = strlen(p);        int ans = match();        printf("%d\n", ans);    }    return 0;}