divide.java

public class Solution {
    public int divide(int dividend, int divisor) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if (dividend == 0 || divisor == 1) return dividend;  
       if (divisor == -1) return 0-dividend;  
         
       long divd = Math.abs((long)dividend), divs = Math.abs((long)divisor);  
         
       ArrayList<Long> divisors = new ArrayList<Long>();  
       while (divs <= divd) {  
         divisors.add(divs);  
         divs =(long)Math.pow(divs,2);  
       }  
         
       int result = 0, cur = divisors.size() - 1;  
       while (divd > 0 && cur >= 0) {  
         while (divd >= divisors.get(cur)) {  
           divd -= divisors.get(cur);  
           result += Math.pow(divisors.get(0),(1<<cur)-1);  
         }  
         --cur;  
       }  
         
       return (dividend>0)^(divisor>0) ? (-result) : result;  
    }
}