Simple C++ Coding Exercise – Use Lookup Table to Eliminate the Condition Checks
There is a popular IQ question, e.g. according to the first few number patterns, find the answer to the input: 1234 = 0 4567 = 1 2345 = 0 …
C++ Coding Example, Using Hash Algorithm to Remove Duplicate Number by O(n)
Hashing is an important technique in Computer Science. There are many cases that you can use Hash to speed up your algorithms (e.g. by reducing from O(n^2) to O(n) …
How Many One’s Between Number 1 to N ?
Question: Given a positive integer (nature number) N, count the number of ‘1’s between number 1 to N inclusive. For example, when N = 2, the answer is 1, …
Fast Power of Two Equal or Larger than a 32-bit Integer
I have seen a naive implementation at work today (written by a colleague). My colleague intends to generate a number that is power of two, and the number is …
High Performance FillChar Method Comparison for 32 bit (every four bytes)
In C/C++, if you want to clear an array by filling a byte-value, you can use the following: void * __cdecl memset(void *_Dst, int Val, size_t _Size) This allows …
Counting the number of Leading Zeros for a 32-bit Integer (Signed or Unsigned)
To count the number of leading zeros for a integer, we can use the following intuitive (bruteforce) method to increment the number of zeros until a first one (from …
