lintcode-medium-Divide Two Integers

Posted 2020-06-26 哥布林工程师

Divide two integers without using multiplication, division and mod operator.

If it is overflow, return 2147483647

 

Given dividend = 100 and divisor = 9, return 11.

 

public class Solution {
    /**
     * @param dividend the dividend
     * @param divisor the divisor
     * @return the result
     */
    public int divide(int dividend, int divisor) {
        // Write your code here
        
        if(divisor == 0)
            return 2147483647;
        
        if(dividend == 0)
            return 0;
        
        if(divisor == 1)
            return dividend;
        
        if (dividend == Integer.MIN_VALUE && divisor == -1) {
            return Integer.MAX_VALUE;
        }
        
        boolean neg = (dividend < 0 && divisor > 0) || (dividend > 0 && divisor < 0);
        
        long num = Math.abs((long) dividend);
        long den = Math.abs((long) divisor);
        
        long result = 0;
        
        while(num >= den){
            int shift = 0;
            
            while(num >= (den << shift))
                shift++;
            
            num -= den<<(shift - 1);
            
            result += 1 << (shift - 1);
        }
        if(neg){
            if(result > Math.abs((long) Integer.MIN_VALUE))
                return 2147483647;
            else    
                return (int) (-result);
        }
        else{
            if(result > (long) Integer.MAX_VALUE)
                return 2147483647;
            else
                return (int) result;
        }
    }
}