dupbyslidingwindow.cpp

#include <iostream>
#include <vector>
using namespace std;

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        int n = nums.size();
        if (k == 0) return false; // No valid window

        // Sliding window as an array (instead of set)
        vector<int> window;
        
        for (int i = 0; i < n; i++) {
            // Check if the number already exists in window
            for (int j = 0; j < window.size(); j++) {
                if (window[j] == nums[i]) {
                    return true;
                }
            }

            // Add current number to the window
            window.push_back(nums[i]);

            // Maintain the window size ≤ k
            if (window.size() > k) {
                // Remove the oldest element (front)
                for (int j = 0; j < window.size() - 1; j++) {
                    window[j] = window[j + 1];
                }
                window.pop_back(); // Remove last element
            }
        }

        return false;
    }
};

int main() {
    int n, k;
    cin >> n;
    vector<int> nums(n);
    
    for (int i = 0; i < n; i++) {
        cin >> nums[i];
    }
    
    cin >> k;

    Solution obj;
    cout << (obj.containsNearbyDuplicate(nums, k) ? "true" : "false") << endl;

    return 0;
}