text: // Source : https://oj.leetcode.com/problems/divide-two-integers/
  // Author : Hao Chen
  // Date   : 2014-06-20
  
  /********************************************************************************** 
  * 
  * Divide two integers without using multiplication, division and mod operator.
  * 
  * If it is overflow, return MAX_INT. 
  *
  **********************************************************************************/
  
  #include <stdio.h>
  #include <string.h>
  #include <iostream>
  using namespace std;
  
  #define INT_MAX     2147483647
  #define INT_MIN     (-INT_MAX - 1)
  
  int divide(int dividend, int divisor) {
  
      int sign = (float)dividend / divisor > 0 ? 1 : -1;
      unsigned int dvd = dividend > 0 ? dividend : -dividend;
      unsigned int dvs = divisor > 0 ? divisor : -divisor;
  
      unsigned int bit_num[32];
      unsigned int i=0;
      long long d = dvs;
      bit_num[i] = d;
      while( d <= dvd ){
          bit_num[++i] = d = d << 1;
      }
      i--;
  
      unsigned int result = 0;
      while(dvd >= dvs){
          if (dvd >= bit_num[i]){
              dvd -= bit_num[i];
              result += (1<<i);
          }else{
              i--;
          }
      }
  
      //becasue need to return `int`, so we need to check it is overflowed or not.
      if ( result > INT_MAX && sign > 0 ) {
          return INT_MAX;
      }
      return (int)result * sign;
  }
  
  
  int main()
  {
      cout << "0/2=" << divide(0, 2) << endl;
      cout << "10/2=" << divide(10, 2) << endl;
      cout << "10/3=" << divide(10, 3) << endl;
      cout << "10/5=" << divide(10, 5) << endl;
      cout << "10/7=" << divide(10, 7) << endl;
      cout << "10/10=" << divide(10, 10) << endl;
      cout << "10/11=" << divide(10, 11) << endl;
      cout << "-1/1=" << divide(1, -1) << endl;
      cout << "1/-1=" << divide(1, -1) << endl;
      cout << "-1/-1=" << divide(-1, -1) << endl;
      cout << "2147483647/1=" << divide(2147483647, 1) << endl;
      cout << "-2147483647/1=" << divide(-2147483647, 1) << endl;
      cout << "2147483647/-1=" << divide(2147483647, -1) << endl;
      cout << "-2147483647/-1=" << divide(-2147483647, -1) << endl;
      cout << "2147483647/2=" << divide(2147483647, 2) << endl;
      cout << "2147483647/10=" << divide(2147483647, 10) << endl;
      cout << "-2147483648/1=" << divide(-2147483648, 1) << endl;
      cout << "-2147483648/-1=" << divide(-2147483648, -1) << endl;
  }
  