题目来源：2017华中农大网络赛 L

L．Happiness

Chicken brother is very happy today, because he attained N pieces of biscuits whosetastes are A or B. These biscuits are put into a box. Now, he can only take out one piece of
biscuit from the box one time. As we all know, chicken brother is a creative man. He wants toput an A biscuit and a B biscuit together and eat them. If he take out an A biscuit from thebox and then he take out a B biscuit continuously, he can put them together and eat happily.
Chicken brother’s happiness will plus one when he eat A and B biscuit together one time.
Now, you are given the arrangement of the biscuits in the box(from top tobottom) ,please output the happiness of Chicken Brother when he take out all biscuit fromthe box.

Input Description

The first line is an integer indicates the number of test cases.In each case, there is one line includes a string consists of characters ‘A’ and ‘B’.
The length of string is not more than 1000000.

Output Description

For each test case:
The first line output “Case #k:”, k indicates the case number.
The second line output the answer.

Sample Input

1
ABABBBA

Sample Output

Case #1:
2

题意概括

给一个字符串，找出其中存在多少个AB这样的子串。

解题思路

搜索一遍就好了。

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <algorithm>using namespace std;char str[1000010];
int main ()
{int t,i,k=0;scanf("%d",&t);while(t--){k++;printf("Case #%d:\n",k);int sum=0;scanf("%s",str);for(i=0;str[i]!='\0';i++){if(str[i]=='A' && str[i+1]=='B'){sum++;}}printf("%d\n",sum);}return 0;
}