LeetCode-Solutions-in-Cpp17

Solutions to high-frequency interview questions of LeetCode in C++17, taking into account both efficiency and comprehensibility.

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• 用哈希表保存已遍历元素，遍历时发现元素已存在哈希表中则说明有重复元素，时间复杂度 O(n)

class Solution {
 public:
  bool containsDuplicate(vector<int>& nums) {
    unordered_set<int> s;
    for (auto& x : nums) {
      if (s.count(x)) {
        return true;
      }
      s.emplace(x);
    }
    return false;
  }
};