汉明间距

/**
* Input: x = 1, y = 4
* Output: 2
* Explanation:
* 1  (0 0 0 1)
* 4  (0 1 0 0)
*         ↑    ↑
* @author yfmei
*
*/
public class HammingDistance {
    public int hammingDistance(int x, int y) {
        //String tr = Integer.toBinaryString(x);
        //二进制转换
        String xStr = toBinary(x);
        String yStr = toBinary(y);
        System.out.println("xStr.length:"+xStr.length()+"  yStr.length:"+yStr.length());
        //位数是否相同
        int diff = getdiff(xStr, yStr);
        if(diff > 0){//x比y大，y从左边开始补0
            yStr = completeBinary(diff,yStr);
        }else{//x比y小，x从左边开始补0
            xStr = completeBinary(-diff,xStr);
        }
        System.out.println("xStr.length:"+xStr.length()+"  yStr.length:"+yStr.length());
        int num = xStr.length();
        int distance = 0;
        for(int i = 0;i < num;i++){
            if(xStr.charAt(i) != yStr.charAt(i)){
                  distance = distance+1;
            }
        }
        return distance;
    }
    public String toBinary(int x) {
        String xStr = "" ;
        while(x > 0){
            xStr = ((x %2 == 0?"0":"1")+xStr);
            x = x / 2;
        }
        return xStr;
    }

    /**

    * 获取位数差

    * @param xStr

    * @param yStr

    * @return

    */

    public int getdiff(String xStr,String yStr) {
        return xStr.length() -yStr.length();
    }

    /**
    * 补足位数
    * @param diff
    * @param str
    * @return
    */
    public String completeBinary(int diff,String str) {
        for(int i = 0;i < diff;i++){
            str = "0"+str;
        }
        return str;
    }

    public static void main(String[] args) {
        HammingDistance hammingDistance = new HammingDistance();
        int distance = hammingDistance.hammingDistance(680142203, 1111953568);
        System.out.println(distance);
        //java提供的计算汉明间距的方法
        System.out.println(Integer.bitCount(680142203 ^ 1111953568));
    }
}