hdu 1381

OJ上分类里说这题是HASH，我用JAVA的TreeSet水过~

import java.util.Scanner;
import java.util.TreeSet;

public class Main {
    public static int work(String str, int N) {
        int len = str.length();
        if(N >= len) {
            return 1;
        }
        TreeSet<String> ts = new TreeSet<String>();
        ts.clear();
        int ans = 0;
        for(int i = 0; i + N <= len; i++) {
            if(ts.add(str.substring(i, i + N))) {
                ans ++;
            }
        }
        return ans;
    }
    public static void main(String[] args) {
        int T, N, NC;
        String str;
        Scanner cin = new Scanner(System.in);
        T = cin.nextInt();
        while(T-- > 0) {
            N = cin.nextInt();
            NC = cin.nextInt();
            str = cin.next();
            System.out.println(work(str, N));
        }
    }
}