pku 1200 Crazy Search(匹配，映射)

#include <iostream>using namespace std;char str[1000000];int chartoint[125];//存储字符和数字的映射bool exist[16000000];//题目中有 maximum number of substrings formed by the possible set of characters does not exceed 16 Millionsint main(){int N,NC,len,cnt=0,temp;scanf("%d%d",&N,&NC);scanf("%s",str);len=strlen(str);int k=0,i=0;memset(chartoint,0,sizeof(chartoint));memset(exist,0,sizeof(exist));while(k!=NC)//计算字符和数字（0,1,2,...,NC-1）的映射{if(chartoint[str[i]]==0) chartoint[str[i]]=k++;i++;}for(i=0;i<len-N+1;i++){temp=0;for(int j=0;j<N;j++)//因为数组在0到NC-1之间，可采用NC进制来计算每个串对应的值{temp=temp*NC+chartoint[str[i+j]];}if(!exist[temp]) cnt++,exist[temp]=true;}printf("%d/n",cnt);return 0;}