使用加法、减法以及一位来实现乘除法

来源：互联网发布：歼16与苏35 知乎编辑：程序博客网时间：2024/04/29 17:06

用+，-, <<, >>来实现 *， / 。

package com.pande.jobhunt.problem;//用+，-, <<, >>来实现 *， / 。public class ImplemeneMultiAndDevideUsingPlusAndShift { public static long multiply(long a, long b) {  long result = 0;  long poistive = 1;  if (a < 0) {   a = -a;   poistive = -poistive;  }  if (b < 0) {   b = -b;   poistive = -poistive;  }  long remain = 0;  while (b > 0) {   remain = b % 2;   result += a * remain;   b = b >> 1;   a = a << 1;  }  return poistive * result; } // a / b public static long divide(long a, long b) {  long result = 0;  long poistive = 1;  if (a < 0) {   a = -a;   poistive = -poistive;  }  if (b < 0) {   b = -b;   poistive = -poistive;  }  while (a >= b) {   long d = 1;   long c = b;   while (c <= a) {    a = a - c;    result += d;    c <<= 1;    d <<= 1;   }  }  return poistive * result; } public static void main(String[] args) {  long t = multiply(-5, -6);  System.out.println(t);  long n = divide(71, 5);  System.out.println(n); }}