In computer science, the Knuth-Morris-Pratt string searching algorithm (or KMP algorithm) searches for occurrences of a "word" W within a main "text string" Sby employing the observation that when a mismatch occurs, the word itself embodies sufficient information to determine where the next match could begin, thus bypassing re-examination of previously matched characters.
Edward is a fan of mathematics. He just learnt the Knuth-Morris-Pratt algorithm and decides to give the following problem a try:
Find the total number of occurrence of the strings "cat" and "dog" in a given string s.
As Edward is not familiar with the KMP algorithm, he turns to you for help. Can you help Edward to solve this problem?
InputThere are multiple test cases. The first line of input contains an integer T (1 ≤ T ≤ 30), indicating the number of test cases. For each test case:
The first line contains a string s (1 ≤ |s| ≤ 1000).
<h4< dd="">OutputFor each case, you should output one integer, indicating the total number of occurrence of "cat" and "dog" in the string.
<h4< dd="">Sample Input7 catcatcatdogggy docadosfascat dogdddcat catcatcatcatccat dogdogdogddddooog dcoagtcat doogdog<h4< dd="">Sample Output
4 1 2 5 3 1 1<h4< dd="">Hint
For the first test case, there are 3 "cat" and 1 "dog" in the string, so the answer is 4.
For the second test case, there is only 1 "cat" and no "dog" in the string, so the answer is 1.
#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
using namespace std;
char a[10005];
int main()
{
int t;
while(cin >> t)
{
int i, j;
for(i = 0; i < t; i++)
{
cin >> a;
int sum = 0;
int len = strlen(a);
for(j = 0; j < len; j++)
{
if(a[j] == 'c' && a[j + 1] == 'a' && a[j + 2] == 't')sum++;
else if(a[j] == 'd' && a[j + 1] == 'o' && a[j + 2] == 'g')sum++;
}
cout << sum << endl;
}
}
return 0;
}
本文介绍了一个基于KMP算法的应用案例,旨在寻找字符串中cat和dog的出现次数。通过具体的输入输出示例,展示了如何利用C++实现这一算法,并提供了完整的代码示例。
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