第一道题暴力AC了。。。

import java.util.Scanner; public class Main { public static int distance(char[] c1, char[] c2, int index) { int distance = 0; int count = c2.length; for (int i = 0; i < count; i++) { if (c1[i + index] != c2[i]) {
                distance++;
            }
        } return distance;
    } public static void main(String[] args) {
        Scanner in = new Scanner(System.in);  char[] c1 = in.nextLine().toCharArray(); char[] c2 = in.nextLine().toCharArray();  int num = c1.length - c2.length+ 1; int total = 0;  for (int i = 0; i < num; i++) {
            total += distance(c1,c2,i);
        }
        System.out.println(total);
    }
}