In a array A
of size 2N
, there are N+1
unique elements, and exactly one of these elements is repeated N
times.
Return the element repeated N
times.
Example 1:
Input: [1,2,3,3] Output: 3
Example 2:
Input: [2,1,2,5,3,2] Output: 2
Example 3:
Input: [5,1,5,2,5,3,5,4] Output: 5
Note:
4 <= A.length <= 10000
0 <= A[i] < 10000
A.length
is even
A:
class Solution { public: int repeatedNTimes(vector<int>& A) { unordered_set<int> S; for(auto v:A){ if(S.find(v) !=S.end()){ return v; } S.insert(v); } return 0;//never hit } };
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