Number of 1’s in bit representation of a number

Bit Manipulation

Objec­tive:  Write an algorithm to count the number of 1’s in the bit representation in given number. Exam­ple: Number: 6 Output: 2 ( 1 1 0) Number: 11 Output: 3 ( 1 0 1 1)  Approach: Method 1: Run Code While number > 0 Keep doing the number & 1, increment count if result is 1 … Read more

Find the two repeating elements in a given array | 6 Approaches

Objective: Given an array of n+2 elements. All elements of the array are in range 1 to n and all elements occur once except two numbers which occur twice. Write an algorithm to find the two repeating numbers. Example: int [] A = {1,4,5,6,3,2,5,2}; int n = 6; Output: Two Repeated elements are: 2 and … Read more

Find a Number occurring odd number of times in a Given array

Objective: Given a array of integers, in which every elements occurs even number of times except one number which occurs add number of times. Find out that number. Example:   int[] A = { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7 }; Element appearing add … Read more

Find a Missing Number From a Sequence of Consecutive Numbers | XOR Method

Input:  Array, arrA[] with a miss­ing num­ber and Range

Out­put : miss­ing number

Example:

int A[] = { 1, 2, 7, 6, 3, 4 };
int range = 7;
Output: MIssing No is :5

In our earlier approach ” Click Here ” we have seen the method where we had calculated the Sum of numbers, but this approach might fail when number goes beyond the integer range.

XOR method will better solution in that case.

Approach: – Time Complexity -O(N), Space Complexity – O(1)

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Generate All Strings of n bits.

Objec­tive: Generate All Strings of n bits, consider A[0..n-1] is an array of size n.

Example :

n = 3
Output:
[0, 0, 0]    [1, 0, 0]    [0, 1, 0]    [1, 1, 0]

[0, 0, 1]     [1, 0, 1]     [0, 1, 1]    [1, 1, 1]

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Find The Missing Duplicate in a Given Array.

Bit Manipulation

Objec­tive: Given an Integer array. Array contains duplicates of all the numbers in array except one number . Find that number.

Example :

int [] A = { 2,1,3,5,5,3,2,1,6,7,7,8,8};
Output : Missing duplicate is 6

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Reverse the binary representation of a number.

Objective: Write a program to Reverse the binary representation of a number

Example:

Input : 30
Output : 15

Explanation:

binary representation of 30 is : 11110
reverse of binary representation : 01111
decimal of reversed binary representation is : 15

Input: A Number

Output: Decimal of reversed binary representation of a number.

Approach:

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