标签：rom seq soft ble ranking nat namespace log microsoft
Problem 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
3
BAPC
BAPC
AZA
AZAZAZA
VERDI
AVERDXIVYERDIAN
Sample Output
1
3
0
题意：给定一个字符串，求它在另一串出现的次数
1 #include <iostream>
2 #include <stdio.h>
3 #include <string.h>
4 using namespace std;
5 const int maxn=1e6+10;
6 int Next[maxn];
7 char str[maxn],mo[maxn];
8 void getNext(){
9 int i=0,j=-1,len=strlen(mo);
10 while(i<len)
11 { if (j==-1||mo[i]==mo[j])
12 Next[++i]=++j;
13 else j=Next[j];
14 }
15 }
16 int kmp(){
17 int i=0,j=0,l1=strlen(str),l2=strlen(mo);
18 int ans=0;
19 while(i<l1)
20 {
21 if(j==-1||mo[j]==str[i])
22 i++,j++;
23 else j=Next[j];
24 if(j==l2) ans++;
25 }
26 return ans;
27 }
28 int main()
29 { int t;
30 scanf("%d",&t);
31 while(t--){
32 scanf("%s%s",mo,str);
33 Next[0]=-1;
34 getNext();
35 //for(int i=0;i<strlen(mo);i++)
36 //cout<<Next[i]<<" "; cout<<endl; 查看next数组
37 printf("%d\n",kmp());
38 }
39 return 0;
40 }
41 /*
42 后人修改过后的KMP算法
43 针对aaaaabcde 模式串：aaaaax
44 int j=0,i=1;
45 next[1]=0;
46 while(i<t[0]) // t[0]存放模式串大小
47 {
48 if(j==0||T[i]==T[j])
49 {
50 i++;
51 j++；
52 if(T[i]!=T[j])
53 next[i]=j;
54 else next[i]=next[j];
55 }
56 else j=next[j];
57 }
58 */
hdoj 1686 Oulipo(kmp)
标签：rom seq soft ble ranking nat namespace log microsoft
原文地址：http://www.cnblogs.com/z-712/p/7306225.html
