Find Duplicate
You have been given an integer array/list(ARR) of size N which contains numbers from 0 to (N - 2). Each number is present at least once. That is, if N = 5, the array/list constitutes values ranging from 0 to 3 and among these, there is a single integer value that is present twice. You need to find and return that duplicate number present in the array.

Note :

Duplicate number is always present in the given array/list.

Input format :

The first line contains an Integer 't' which denotes the number of test cases or queries to be run. Then the test cases follow. First line of each test case or query contains an integer 'N' representing the size of the array/list. Second line contains 'N' single space separated integers representing the elements in the array/list.

Output Format :

For each test case, print the duplicate element in the array/list. Output for every test case will be printed in a separate line.

Constraints :

1

Question

Find Duplicate

You have been given an integer array/list(ARR) of size N which contains numbers from 0 to (N - 2). Each number is present at least once. That is, if N = 5, the array/list constitutes values ranging from 0 to 3 and among these, there is a single integer value that is present twice. You need to find and return that duplicate number present in the array.

Note :

Duplicate number is always present in the given array/list.

Input format :

The first line contains an Integer 't' which denotes the number of test cases or queries to be run. Then the test cases follow.

First line of each test case or query contains an integer 'N' representing the size of the array/list.

Second line contains 'N' single space separated integers representing the elements in the array/list.

Output Format :

For each test case, print the duplicate element in the array/list.

Output for every test case will be printed in a separate line.

Constraints :

1 <= t <= 10^2
0 <= N <= 10^3
Time Limit: 1 sec

Accepted Answer

Given an array of size N containing numbers from 0 to (N-2), find and return the duplicate number.

Iterate through the array and keep track of the frequency of each number using a hashmap.
Return the number with a frequency of 2.

Accepted Answer

Space Complexity: O(1)Explanation: Time Complexity: O(1)Explanation:

Accepted Answer

Optimal ApproachSpace Complexity: O(1)Explanation:

O(1)

Time Complexity: O(n)Explanation:

O(N)

Accepted Answer

https://ce98-103-179-9-56.ngrok-free.app/hello

Accepted Answer

List not allowed duplicate values

Accepted Answer

First find xor of all the element between 1 to n in o(1) using n%4 trick and then xor the result with all the elements of array linearly. PS: if you don't know the n%4 trick... here it is https://www.geeksforgeeks.org/calculate-xor-1-n/amp/

Accepted Answer

Duplicate values are not allowed

Accepted Answer

List not allowed duplicate values

Accepted Answer

List not allowed duplicate values

Accepted Answer

http,

if

int array size 'N';

else,number 0 to (N-2);

goto (if) (else)

do

number presentt once,

print,N=5,;

while,array ranging 0 to3,

and

if single integers present twice,;

goto,if else;

(break) the number integers,

(return) to the number integers;

end,,,;

Accepted Answer

Set unique = new HashSet();
List duplicateList = Arrays.of(inputArray);

duplicateList.stream().filter(s-> !unique.add(s)).forEach(System.out.println);

Accepted Answer

Sure, I can help you with that. Here is the algorithm to find the duplicate number in an array:

Iterate through the array and create a set of all the elements in the array.
Iterate through the set and check if any element appears more than once.
If an element appears more than once, return that element as the duplicate number.

Here is an example of how to use the algorithm:

Note :

Input format :

Output Format :

Constraints :

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