Example: Brute-Force Duplicate Finder in C++

// Brute-Force Duplicate Finder
    #include <iostream>
    #include <vector>
    #include <numeric> // For std::iota (not used in this specific example but good to include)

    int findDuplicateBruteForce(const std::vector<int>& nums) {
        // Step 1: Iterate through each element
        for (size_t i = 0; i < nums.size(); ++i) {
            // Step 2: Compare with all subsequent elements
            for (size_t j = i + 1; j < nums.size(); ++j) {
                // Step 3: If a duplicate is found, return it
                if (nums[i] == nums[j]) {
                    return nums[i];
                }
            }
        }
        // Step 4: If no duplicate found (shouldn't happen with problem constraints)
        return -1; 
    }

    int main() {
        std::vector<int> nums = {1, 3, 4, 2, 2}; // n = 5, range [1, 4]
        int duplicate = findDuplicateBruteForce(nums);

        if (duplicate != -1) {
            std::cout << "The duplicate number is: " << duplicate << std::endl;
        } else {
            std::cout << "No duplicate found." << std::endl;
        }

        std::vector<int> nums2 = {3, 1, 3, 4, 2}; // Another example
        duplicate = findDuplicateBruteForce(nums2);
        if (duplicate != -1) {
            std::cout << "The duplicate number is: " << duplicate << std::endl;
        } else {
            std::cout << "No duplicate found." << std::endl;
        }

        return 0;
    }