Tag Archives: Others

Find the first N prime numbers. (Method 1)

Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 Today let us discuss about a very common but very interesting problem “To find prime numbers in first N Natural numbers “. I will be taking here a… Read More »

Reverse bits in an unsigned integer

Question: Given an unsigned Integer, you need to reverse its bits. There are several methods of reversing the bits of an unsigned integer. Here, we devise an algorithm using the XOR swap trick. Hint: How do you swap the ith bit with the jth bit? Try to figure out if you could use the XOR operation to do… Read More »

Playing with Pointers

Question: What is a Pointer? What are its limitations? What are its benefits? How do we use it? What all operation we can perform using it? In this article we are going to discover answers to all these questions. Pointer is a variable that contain the address of another variable and that variable can be a structure, array… Read More »

Longest substring without repeating characters

Question: Given a string, find the length of the longest substring without repeating characters. Input: “abcabcbb” Output: “abc” Input: “bbbb” Output: “b” The longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3. For “bbbbb” the longest substring is “b”, with the length of 1. We definitely have the brute-force method, where we find… Read More »

Make a fair coin from a biased coin.

Question: You are given a function foo() that represents a biased coin. When foo() is called, it returns 0 with 60% probability, and 1 with 40% probability. Write a new function that returns 0 and 1 with 50% probability each. Your function should use only foo(), no other library method. We know foo() returns 0 with 60% probability.… Read More »

C cannot have static structure members

In C, a structure cannot have static members, but in C++ a structure can have static members. For example, following program causes compilation error in C, but works in C++. Feel free to add your opinion.

Symbol Table Implementations

Symbol Tables can be implemented in many ways and here are some of them. Unordered Array Implementation With this method, just maintaining an array is enough. It needs O(n) time for searching, insertion and deletion in the worst case. Ordered [Sorted] Array Implementation In this we maintain a sorted array of keys and values. Store in sorted order… Read More »

Symbol Tables

Since childhood, we have all used a dictionary, and many of us have used a word processor (say Microsoft WORD) which comes with a spell checker. The spell checker is also a dictionary but limited. There are many real time examples for dictionaries and few of them are:- Spelling checker The data dictionary found in database management applications… Read More »