If you have any query feel free to chat us!
Happy Coding! Happy Learning!
To find a duplicate number in an array, you can use various approaches depending on the constraints and requirements of the problem. Here are three common methods to find a duplicate number in an array:
- Using Hash Set: You can use a hash set to keep track of elements seen so far while traversing the array. If an element is already in the hash set, it means it is a duplicate.
Here's the C++ code to find the duplicate number using a hash set:
cppCopy code
#include <iostream> #include <vector> #include <unordered_set> int findDuplicate(std::vector<int>& nums) { std::unordered_set<int> seen; for (int num : nums) { if (seen.count(num) > 0) { return num; } seen.insert(num); } return -1; // No duplicate found } int main() { std::vector<int> nums = {1, 3, 4, 2, 2}; int duplicate = findDuplicate(nums); if (duplicate != -1) { std::cout << "Duplicate number: " << duplicate << std::endl; } else { std::cout << "No duplicate found." << std::endl; } return 0; }
- Using Sorting: Sort the array first, and then traverse it to find adjacent elements with the same value. The duplicate number will be found during the traversal.
Here's the C++ code to find the duplicate number using sorting:
cppCopy code
#include <iostream> #include <vector> #include <algorithm> int findDuplicate(std::vector<int>& nums) { std::sort(nums.begin(), nums.end()); for (int i = 1; i < nums.size(); i++) { if (nums[i] == nums[i - 1]) { return nums[i]; } } return -1; // No duplicate found } int main() { std::vector<int> nums = {1, 3, 4, 2, 2}; int duplicate = findDuplicate(nums); if (duplicate != -1) { std::cout << "Duplicate number: " << duplicate << std::endl; } else { std::cout << "No duplicate found." << std::endl; } return 0; }
- Using Floyd's Tortoise and Hare Algorithm (Cycle Detection): If the array contains elements from 1 to n, you can treat the array as a linked list, where the value of each element represents the next index. In this case, there will be a cycle if there is a duplicate element.
Here's the C++ code to find the duplicate number using Floyd's Tortoise and Hare Algorithm:
cppCopy code
#include <iostream> #include <vector> int findDuplicate(std::vector<int>& nums) { int slow = nums[0]; int fast = nums[0]; do { slow = nums[slow]; fast = nums[nums[fast]]; } while (slow != fast); slow = nums[0]; while (slow != fast) { slow = nums[slow]; fast = nums[fast]; } return slow; } int main() { std::vector<int> nums = {1, 3, 4, 2, 2}; int duplicate = findDuplicate(nums); if (duplicate != -1) { std::cout << "Duplicate number: " << duplicate << std::endl; } else { std::cout << "No duplicate found." << std::endl; } return 0; }
All three methods can effectively find a duplicate number in an array. The choice of the method depends on the specific problem constraints and requirements.
Comments: 2
SCIAKU Team please upload 1st video of TREE please please please, please
I bought this course, it worth it!
Hi i want to buy this course but you dont have master card payment method please let me know how i can buy it
Dear mk.info.work, Now we have all types of payment options. If you need to purchase just checkout our official website