leetcode/src/divideTwoInt/divideTwoInt.cpp at master · AndyleeSharp/leetcode · GitHub

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// 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.

**********************************************************************************/

#include <stdio.h>

#include <string.h>

#include <iostream>

using namespace std;

int divide(int dividend, int divisor) {

int sign = 1;

long long dvd = dividend;

long long dvs = divisor;

if (dvd<0) {

dvd = -dvd;

sign = -sign;

}

if (dvs<0) {

dvs = -dvs;

sign = -sign;

}

long long bit_num[32];

memset( bit_num, 0, sizeof(bit_num)/sizeof(bit_num[0]) );

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--;

}

return result * sign;

}

int main()

{

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 << "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;

}

leetcode/src/divideTwoInt/divideTwoInt.cpp at master · AndyleeSharp/leetcode · GitHub

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