# 217.Contains Duplicate

**217.Contains Duplicate**

难度:Easy

> 给定一个整数数组，判断是否存在重复元素。

如果任何值在数组中出现至少两次，函数返回 true。如果数组中每个元素都不相同，则返回 false。

```
示例 1:

输入: [1,2,3,1]
输出: true
示例 2:

输入: [1,2,3,4]
输出: false
示例 3:

输入: [1,1,1,3,3,4,3,2,4,2]
输出: true
```

主要方式是计数，可以通过集合来解决。

```
class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        unordered_set<int>map(nums.begin(), nums.end());
        return map.size() < nums.size();
    }
};
```

> 执行用时 :92ms, 在所有 C++ 提交中击败了20.51%的用户\
> 内存消耗 :16MB, 在所有 C++ 提交中击败了54.20%的用户


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