历届试题 翻硬币

import java.util.Scanner;

public class Main {
    static String str1;
    static String str2;

    public static int[] Check(){
        int[] checked = new int[str1.length()];
        char[] ch1 = str1.toCharArray();
        char[] ch2 = str2.toCharArray();
        for ( int i = 0 ; i < checked.length ; i++){
            if ( ch1[i] == ch2[i]){
                checked[i] = 0;
            }else{
                checked[i] = 1;
            }
        }
        return checked;
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        str1 = in.next();
        str2 = in.next();
        int[] checked = Check();
        int flag = -1;
        int cnt = 0;

        for ( int i = 0 ; i < checked.length ; i++){
            if(checked[i] == 1){
                if ( flag == -1){
                    //flag = -1 表示i之前没有1的或者已经成对。
                    flag = i;
                }else{
                    cnt += i - flag;
                    flag = -1;
                }
            }
        }
        System.out.print(cnt);
        in.close();
    }

}