poj 1200 crazy search Hash

Problem: 1200		User: sunyanfei
Memory: 30904K		Time: 63MS
Language: G++		Result: Accepted

• Source Code

/*
 * Author:lonelycatcher
 * Problem:poj 1200 crazy search
 * Type:Hash
 */
#include <iostream>
#include<string>
#include<string.h>
#include<stdio.h>
using namespace std;
char str[1000000];
int hash[16000000];
int ansi[256]={0};
int main()
{
	int N,NC,ans=0,i,j;
	setbuf(stdout,NULL);
	scanf("%d%d%s",&N,&NC,str);
	int len=strlen(str);
	for(i=0;i<len;i++)
	{
		ansi[(int)str[i]]=1;
	}
	int cnt=0;
	for(i=0;i<256;i++)
	{
		if(ansi[i])
			ansi[i]=cnt++;
	}
	for(i=0;i<=len-N;i++)
	{
        int key=0;
        for(j=0;j<N;j++)
        {
        	key=key*NC+ansi[(int)str[i+j]];//转换成NC进制
        }
        if(!hash[key])
        {
        	ans++;
        	hash[key]=1;
        }
	}
	printf("%d\n",ans);
	return 0;
}