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// 137. Single Number II
#include "leetcode.h"
/*
* given an integer array 'nums' where every element appears three times except
* for one, which appears exactly once. find the single element and return it.
* you must implement a solution with a linear runtime complexity and use only
* constant extra space.
*/
class Solution {
public:
int singleNumber(vector<int> &nums) {
unordered_map<int, int> um;
for (auto i : nums)
um[i]++;
for (auto i : um)
if (i.second == 1)
return i.first;
return -1;
}
};
int main() {
Solution obj;
vector<int> n1 = {2, 2, 3, 2}, n2 = {0, 1, 0, 1, 0, 1, 99};
printf("%d\n", obj.singleNumber(n1)); // expect: 3
printf("%d\n", obj.singleNumber(n2)); // expect: 99
}
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