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two-sum-iii-data-structure-design

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Description

https://leetcode.com/problems/two-sum-iii-data-structure-design/

Solution

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class TwoSum {
public:
    unordered_map<int, int> counter;
    /** Initialize your data structure here. */
    TwoSum() {
        
    }
    
    /** Add the number to an internal data structure.. */
    void add(int number) {
        counter[number] += 1;
    }
    
    /** Find if there exists any pair of numbers which sum is equal to the value. */
    bool find(int value) {
        for (auto& item : counter) {
            int left = item.first;
            int right = value - left;
            if (left == right && item.second >= 2) return true;
            if (left != right && counter.count(right) != 0) return true;
            
        }
        
        return false;
    }
};

/**
 * Your TwoSum object will be instantiated and called as such:
 * TwoSum obj = new TwoSum();
 * obj.add(number);
 * bool param_2 = obj.find(value);
 */