1093.Count PAT's (25)...to be continued...

来源：互联网发布：网络终端机改造编辑：程序博客网时间：2024/05/17 21:45

1093.Count PAT’s (25)…to be continued…

pat-al-1093

2017-03-02

乙级好像有这题
暴力会超时，对于每个A，只要知道它前面多少个P和后面有多少T

/** * pat-al-1093 * 2017-03-02 * Cpp version * Author: fengLian_s */#include<stdio.h>#include<string.h>#define MAX 100010int main(){  freopen("in.txt", "r", stdin);  char str[MAX];  scanf("%s", str);  int numOfP[MAX] = {0};  int len = strlen(str);  for(int i = 0;i < len;i++)  {    if(i > 0 && str[i] == 'P')    {      numOfP[i] = numOfP[i-1]+1;    }    else if(i == 0 && str[i] == 'P')    {      numOfP[i] = 1;    }    else      numOfP[i] = numOfP[i-1];    //printf("i: %d\n", numOfP[i]);  }  int numOfT = 0;  int ans = 0;  for(int i = len-1;i >= 0;i--)  {    if(i == len-1 && str[i] == 'T')      numOfT = 1;    else if(i < len-1 && str[i] == 'T')      numOfT++;    else if(str[i] == 'A')    {      ans += (numOfT * numOfP[i]);      ans %= 1000000007;    }  }  printf("%d\n", ans);  return 0;}

-TBC-

0 0