文章目录
一、题目
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Example 1:
Input: nums = [1,2,3,1]
Output: true
Example 2:
Input: nums = [1,2,3,4]
Output: false
Example 3:
Input: nums = [1,1,1,3,3,4,3,2,4,2]
Output: true
Constraints:
1 <= nums.length <= 105
-109 <= nums[i] <= 109
二、题解
cpp
class Solution {
public:
bool containsDuplicate(vector<int>& nums) {
unordered_map<int,int> map;
for(auto x:nums){
if(map[x] == 1) return true;
map[x]++;
}
return false;
}
};