Coding interview:位运算

位运算总结

1.交换两个数
2.选择两个数中较大的一个
3.位运算进行加减乘除
下面给出代码

//交换两个数
public void swap(int a,int b) {
        a = a^b;
        b = a^b;
        a = a^b;
        System.out.println("a: " + a + " , b:" + b);
    }

//获取两个数较大的
    int getMax(int a,int b) {
        int c = a - b;
        int sign = (c>>31) & 1;
        int flag = sign ^ 1;
        return a * flag + b * sign;
    }
//加法
    int add(int a,int b){
        while(b != 0){
            int c = a ^ b;
            b = (a & b)<<1;
            a = c;
        }
        return a;
    }
    //减法
    int minus(int a,int b){
        return add(a,add(~b,1));
    }
//乘法
    int multiply(int a,int b) {
        int res = 0;
        while(b!=0){
            if((b&1)==1){
                res = add(res,a);
            }
            a <<= 1;
            b >>>= 1;
        }
        return res;
    }
//除法
  int div(int a,int b){
        int signA = (a>>31) & 1;
        int signB = (b>>31) & 1;
        if (signA == 1){
            a = add(~a,1);
        }
        if (signB == 1) {
            b = add(~b,1);
        }
        int res = 0;
        long c = b;
        for(int i=30;i>=0;i=minus(i,1)) {
            if(a < (c<<i)) continue;
            else{
                res = add(res,1<<i);
                a = minus(a,b<<i);
            }
        }
        if (signA==1) {
            res = add(~res,1);
        }
        if (signB==1) {
            res = add(~res,1);
        }
        return res;
    }
    public static void main(String[]args) {
        BitOper bitOper = new BitOper();
        bitOper.swap(1,2);
        System.out.println(bitOper.getMax(101,12));
        System.out.println(bitOper.add(9999,1));
        System.out.println(bitOper.minus(1020,9999));
        System.out.println(bitOper.multiply(-11,-2));
        System.out.println(bitOper.div(11,3));
    }