博客
关于我
1093 Count PAT‘s (25分) 含DP做法
阅读量:376 次
发布时间:2019-03-05

本文共 1694 字,大约阅读时间需要 5 分钟。

1093 Count PAT’s (25分)

The string APPAPT contains two PAT’s as substrings. The first one is formed by the 2nd, the 4th, and the 6th characters, and the second one is formed by the 3rd, the 4th, and the 6th characters.

Now given any string, you are supposed to tell the number of PAT’s contained in the string.

Input Specification:

Each input file contains one test case. For each case, there is only one line giving a string of no more than 10 ^ ​5 characters containing only P, A, or T.

Output Specification:

For each test case, print in one line the number of PAT’s contained in the string. Since the result may be a huge number, you only have to output the result moded by 1000000007.

Sample Input:

APPAPT

Sample Output:

2

方法一:题目意思就是找出一个A左边的P个数*右边的T,构造两个数组分别存储在字符串i位置左边P的个数和右边T的个数,然后遍历字符串将合理位置的两个数组的数乘起来相加即可,不要忘了最后模1000000007,设字符串长度N ,整个复杂度就是遍历了三遍字符串所以还是O(N)的,不会超时。这种做法比较直接,也比较容易想到

AC代码

#include
#include
#include
using namespace std;#define N 1000000007typedef long long LL;string m;int main(){ LL res=0; cin >> m; vector
a(m.size(),0); vector
b(m.size(),0); for(int i=1;i
=0;i--) if(m[i+1]=='T') b[i]=b[i+1]+1; else b[i]=b[i+1]; for(int i=0;i

方法二:DP

#include
#include
#include
using namespace std;#define N 1000000007char s[100010],p[]=" PAT";int f[100010][4];int main(){ cin >> s+1; int n=strlen(s+1); f[0][0]=1; for(int i=1;i<=n;i++) for(int j=0;j<=3;j++) { f[i][j]=f[i-1][j]; if(s[i]==p[j]) f[i][j]=(f[i][j]+f[i-1][j-1])%N; } cout << f[n][3]; return 0;}

转载地址:http://azbwz.baihongyu.com/

你可能感兴趣的文章
memcached高速缓存学习笔记003---利用JAVA程序操作memcached crud操作
查看>>
Memcached:Node.js 高性能缓存解决方案
查看>>
memcache、redis原理对比
查看>>
memset初始化高维数组为-1/0
查看>>
Metasploit CGI网关接口渗透测试实战
查看>>
Metasploit Web服务器渗透测试实战
查看>>
MFC模态对话框和非模态对话框
查看>>
Moment.js常见用法总结
查看>>
MongoDB出现Error parsing command line: unrecognised option ‘--fork‘ 的解决方法
查看>>
mxGraph改变图形大小重置overlay位置
查看>>
MongoDB可视化客户端管理工具之NoSQLbooster4mongo
查看>>
Mongodb学习总结(1)——常用NoSql数据库比较
查看>>
MongoDB学习笔记(8)--索引及优化索引
查看>>
mongodb定时备份数据库
查看>>
mppt算法详解-ChatGPT4o作答
查看>>
mpvue的使用(一)必要的开发环境
查看>>
MQ 重复消费如何解决?
查看>>
mqtt broker服务端
查看>>
MQTT 保留消息
查看>>
MQTT 持久会话与 Clean Session 详解
查看>>