349. Intersection of Two Arrays

// It can't AC, and I can't find bugs...


class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        if (!(nums1.size())) return nums1;
        if (!(nums2.size())) return nums2;
        int nums1_max = *max_element(nums1.begin(),nums1.end());
        int nums2_max = *max_element(nums2.begin(),nums2.end());
        int n1 = nums1.size(), n2 = nums2.size();
        int standard = (n1 > n2 ? n1 : n2) + 1;
        int table_size = nums1_max > nums2_max ? nums1_max : nums2_max;
        int* table = new int[table_size]();
        
        for (int i = 0; i < n1; i++)
        {
            if (table[nums1[i]]) table[nums1[i]]++;
            else table[nums1[i]] = standard + 1;
        }
        for (int i = 0; i < n2; i++)
        {
            table[nums2[i]]--;
        }
        
        vector<int> intersection;
        for (int i = 0; i < table_size; i++)
        {
            if (table[i] == standard) intersection.push_back(i);
        }
        
        return intersection;
    }
};



// 16 ms

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        set<int> s_nums1(nums1.begin(),nums1.end());
        set<int> s_nums2(nums2.begin(),nums2.end());
        vector<int> ans;
        set_intersection(s_nums1.begin(),s_nums1.end(),
                        s_nums2.begin(),s_nums2.end(),
                        back_inserter(ans));
        return ans;
}
};