Let's write code to find a single number from the array, we use the XOR technique to solve this problem in C#. public static int SingleNumber(int[] nums) { // Initialize result to 0. This will hold the unique number. int result = 0; // Loop through each number in the array foreach (int num in nums) { // XOR the current number with the result // This will cancel out numbers that appear twice and leave the unique number result ^= num; } // Return the unique number found return result; } If I take the array [2, 2, 1]. Step-by-Step Execution Initialization: Initial State: result = 0We start with result initialized to 0. First Iteration (num = 2): Operation: result ^= 2 which means result = result ^ 2Calculation: 0 ^ 2 = 2 (since 0 XOR anything equals that thing)State after iteration: result = 2 Second Iteration (num = 2): Operation: result ^= 2 which means result = result ^ 2Calculation: 2 ^ 2 = 0 (since a XOR a = 0)State after iteration: result = 0 Third Iteration (num = 1): Operation: result ^= 1 which means result = result ^ 1Calculation: 0 ^ 1 = 1 (since 0 XOR anything equals that thing)State after iteration: result = 1 Final Result return result; Return Value: 1 and

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Single Number find

Steilla Mitchel 322 12-Jun-2024

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

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Updated on 12-Jun-2024

Steilla Mitchel

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Ravi Vishwakarma

12-Jun-2024

Let's write code to find a single number from the array, we use the XOR technique to solve this problem in C#.

public static int SingleNumber(int[] nums)
{
    // Initialize result to 0. This will hold the unique number.
    int result = 0;

    // Loop through each number in the array
    foreach (int num in nums)
    {
        // XOR the current number with the result
        // This will cancel out numbers that appear twice and leave the unique number
        result ^= num;
    }

    // Return the unique number found
    return result;
}

If I take the array [2, 2, 1].

Step-by-Step Execution

Initialization:

Initial State: result = 0
We start with result initialized to 0.

First Iteration (num = 2):

Operation: result ^= 2 which means result = result ^ 2
Calculation: 0 ^ 2 = 2 (since 0 XOR anything equals that thing)
State after iteration: result = 2

Second Iteration (num = 2):

Operation: result ^= 2 which means result = result ^ 2
Calculation: 2 ^ 2 = 0 (since a XOR a = 0)
State after iteration: result = 0

Third Iteration (num = 1):

Operation: result ^= 1 which means result = result ^ 1
Calculation: 0 ^ 1 = 1 (since 0 XOR anything equals that thing)
State after iteration: result = 1

Final Result

return result;

Return Value: 1