Contents
How do you find the equal pair of an array?
Efficient Approach
- Create an empty hash table (unordered_map in C++, HashMap in Java, Dictionary in Python)
- Store frequencies of all elements.
- Traverse through the hash table. For every element, find its frequency. Increment the result by frequency/2 for every element,
How do you find the frequency of an element in an array?
Algorithm
- Declare and initialize an array arr.
- Declare another array fr with the same size of array arr.
- Variable visited will be initialized with the value -1.
- The frequency of an element can be counted using two loops.
- Initialize count to 1 in the first loop to maintain a count of each element.
How do you print a pair in an array?
Print all pairs with given sum
- A simple solution is to traverse each element and check if there’s another number in the array which can be added to it to give sum.
- Method 2 (Use hashing). We create an empty hash table.
- Method 3. Another method to Print all pairs with the given sum is given as follows:
How do you find all distinct pairs in an array?
Efficient approach: First find out the number of unique elements in an array. Let the number of unique elements be x. Then, the number of unique pairs would be x2. This is because each unique element can form a pair with every other unique element including itself.
How do you find the number of unique pairs?
Explanation: To find the number of unique pairs in a set, where the pairs are subject to the commutative property (AB = BA) , you can calculate the summation of 1 + 2 + + (n-1) where n is the number of items in the set.
How do you find the frequency of a number in an array C++?
- Create an array of integer type variables.
- Calculate the size of an array using size() function.
- Create a variable of type unordered_map let’s say um.
- Start loop FOR from i to 0 and till size.
- Inside the loop, set um[arr[i]]++
- Start another loop for from auto x till um.
- Inside the loop, print the frequency.
https://www.youtube.com/watch?v=8wrlCL6cvfQ