29.Divide Two Integers

[niuworld]

Question:

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

If it is overflow, return MAX_INT.

Solution:

class Solution {
public:
    int divide(int dividend, int divisor) {
        if (divisor == 0 ) return INT_MAX;
        bool neg = (dividend >= 0 && divisor < 0 ) || (dividend <= 0 && divisor > 0);
        unsigned int u_dividend = (dividend >= 0)? dividend: -dividend;
        unsigned int u_divisor = (divisor >= 0)? divisor: -divisor;
        unsigned int res = 0;
        for ( int i = 31 ; i >= 0; i--){
              if ( ( u_dividend >> i) >= u_divisor){
                res += (1 << i) ;
                u_dividend = u_dividend - (u_divisor<<i);
              }
        }
        if(neg){
            if( res > ((unsigned int) ( 1 << 31)))
            return INT_MAX;
            else return -res;
        }
        else {
            if( res > INT_MAX) return INT_MAX;
            else return res;
        }
    }
};

Note: INT_MAX = 2^31 -1; INT_MIN = -2^31;

The result should be between INT_MIN and INT_MAX