Leetcode number Subtraction by Fangkaigen number

Attention needs to be paid to overflow, especially the integer.min_value number.

The dichotomy needs to be mastered.

Divide without division, the powers of divide and conquer

2. Add the Numbers

You are given, linked lists representing, and non-negative numbers. The digits is stored in reverse order and all of their nodes contain a single digit. ADD the numbers and return it as a linked list.

Input: (2, 4, 3) + (5, 6, 4)
Output:7, 0, 8

Basically equals merge array, remember to add carry bit at last.

There is no need to consider overflow, but remember to output 0 instead of an empty list when entering two empty lists.

Divide-Integers

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

If It is overflow, return max_int.

You cannot use division to divide, so that the divisor is multiplied by two until it is greater than dividend.

The core code is as follows:

 while (x >= y) {    int a = 0;      while (x >= (y << a)) {        a+ +;    }    A--;     + = (long) 1 << a    ; -= y << A;    }

where x is the divisor, y is the divisor, and in this code, you need to note that x, Y is a long. 1 to be cast to long

This problem has a lot of corner case, specifically see

[Leetcode] 29. Divide integers

Multiply Strings

Given numbers represented as strings, return multiplication of the numbers as a string.

Note:

• The numbers can arbitrarily large and is non-negative.
• Converting the input string to integer are not allowed.
• You should don't use internal library such as BigInteger.
• According to my current solution there is no corner case to consider, as long as the output number in front of the extra 0 to remove it. But now the solution is relatively slow. You can improve it when you are free.

Pow (x, N)

Implement Pow (x, n).

1.0 of the 0-time party is 1

2. Determine if x is 0,n whether 0,x is 1

3. Judge the positive and negative of x, and determine the positive and negative of N.

4. Note that n is the case of Integer.min_value, in which case the absolute value is overflow

Btw,double.min_value defines the minimum positive number that is greater than 0 Oh ~

Leetcode TestCase is not related to double overflow, double overflow directly return to Max_value?

Leetcode number Subtraction by Fangkaigen number