LeetCode - 29. Divide Two Integers 29. Divide Two Integers Problem's Link

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Mean: 

不使用乘法、除法、取模运算，实现两个数相除.

analyse:

使用移位运算.

Time complexity: O(N)

view code

/**

* -----------------------------------------------------------------

* Copyright (c) 2016 crazyacking.All rights reserved.

*       Author: crazyacking

*       Date  : 2016-02-19-17.45

*/

#include <queue>

#include <cstdio>

#include <set>

#include <string>

#include <stack>

#include <cmath>

#include <climits>

#include <map>

#include <cstdlib>

#include <iostream>

#include <vector>

#include <algorithm>

#include <cstring>

using namespace std;

typedef long long(LL);

typedef unsigned long long(ULL);

const double eps(1e-8);

class Solution

{

public:

   int divide(int dividend, int divisor)

   {

       if(!divisor || (dividend==INT_MIN && divisor==-1))

           return INT_MAX;

       bool sign=(dividend<0)^(divisor<0);

       long long dvd=labs(dividend);

       long long dvs=labs(divisor);

       int res=0;

       while(dvd>=dvs)

       {

           long long tmp=dvs,multiple=1;

           while(dvd>=(tmp<<1))

           {

               tmp<<=1;

               multiple<<=1;

           }

           dvd-=tmp;

           res+=multiple;

       }

       return sign?-res:res;

   }

};

int main()

   Solution solution;

   int a,b;

   while(cin>>a>>b)

       cout<<solution.divide(a,b)<<endl;

   return 0;

}

/*