网址:http://codeforces.com/problemset/problem/1287/A
It's a walking tour day in SIS.Winter, so tt groups of students are visiting Torzhok. Streets of Torzhok are so narrow that students have to go in a row one after another.
Initially, some students are angry. Let's describe a group of students by a string of capital letters "A" and "P":
- "A" corresponds to an angry student
- "P" corresponds to a patient student
Such string describes the row from the last to the first student.
Every minute every angry student throws a snowball at the next student. Formally, if an angry student corresponds to the character with index ii in the string describing a group then they will throw a snowball at the student that corresponds to the character with index i+1i+1 (students are given from the last to the first student). If the target student was not angry yet, they become angry. Even if the first (the rightmost in the string) student is angry, they don't throw a snowball since there is no one in front of them.
Let's look at the first example test. The row initially looks like this: PPAP. Then, after a minute the only single angry student will throw a snowball at the student in front of them, and they also become angry: PPAA. After that, no more students will become angry.
Your task is to help SIS.Winter teachers to determine the last moment a student becomes angry for every group.
The first line contains a single integer tt — the number of groups of students (1≤t≤1001≤t≤100 ). The following 2t2t lines contain descriptions of groups of students.
The description of the group starts with an integer kiki (1≤ki≤1001≤ki≤100 ) — the number of students in the group, followed by a string sisi , consisting of kiki letters "A" and "P", which describes the ii -th group of students.
For every group output single integer — the last moment a student becomes angry.
1 4 PPAP
1
3 12 APPAPPPAPPPP 3 AAP 3 PPA
4 1 0
In the first test, after 11 minute the state of students becomes PPAA. After that, no new angry students will appear.
In the second tets, state of students in the first group is:
- after 11 minute — AAPAAPPAAPPP
- after 22 minutes — AAAAAAPAAAPP
- after 33 minutes — AAAAAAAAAAAP
- after 44 minutes all 1212 students are angry
In the second group after 11 minute, all students are angry.
解题思路:
就是在字符串中找A并且向后枚举,找他能向后传染的最大值
#pragma GCC optimize(2) #include<bits/stdc++.h> using namespace std; inline int read() {int x=0,f=1;char c=getchar();while(c!='-'&&(c<'0'||c>'9'))c=getchar();if(c=='-')f=-1,c=getchar();while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar();return f*x;} typedef long long ll; const int maxn = 1e7+10; char a[maxn]; int main() { int t; cin>>t; while(t--){ int n; cin>>n; scanf("%s",a); int ans=0; int k=0; for(int i=0;i<n;i++){ if(a[i]=='A'){ while(a[i+1]=='P'){ k++; i++; } } ans=max(k,ans); k=0; } printf("%d ",ans); } return 0; }