#include "leetcode.h" class Solution { public: bool containsNearbyDuplicate(vector &nums, int k) { unordered_map um; for (int i = 0; i < nums.size(); i++) { if (um.count(nums[i])) if (abs(i - um[nums[i]]) <= k) return true; um[nums[i]] = i; } return false; } }; int main() { Solution obj; vector nums = {1, 2, 3, 1}; if (obj.containsNearbyDuplicate(nums, 3)) cout << "true"; else cout << "false"; }