[Lintcode] Intersection of two Arrays two arrays intersect

Given the arrays, write a function to compute their intersection.
Notice

Each element in the result must is unique.
The result can be on any order.

Has you met this question in a real interview?
Example

Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2].
Challenge

Can you implement it in three different algorithms?

Leetcode on the original topic, please see my previous blog intersection of the Arrays.

Solution One:

classSolution { Public:    /** * @param nums1 an integer array * @param nums2 a integer array * @return an integer array*/Vector<int> Intersection (vector<int>& Nums1, vector<int>&nums2) {        Set<int>s, Res;  for(Auto a:nums1) S.insert (a);  for(Auto a:nums2) {if(S.count (a)) Res.insert (a); }        returnvector<int>(Res.begin (), Res.end ()); }};

Solution Two:

classSolution { Public:    /** * @param nums1 an integer array * @param nums2 a integer array * @return an integer array*/Vector<int> Intersection (vector<int>& Nums1, vector<int>&nums2) {Vector<int>Res; inti =0, j =0;        Sort (Nums1.begin (), Nums1.end ());        Sort (Nums2.begin (), Nums2.end ());  while(I < Nums1.size () && J <nums2.size ()) {            if(Nums1[i] < Nums2[j]) + +i; Else if(Nums1[i] > Nums2[j]) + +J; Else {                if(Res.empty () | | Res.back ()! =Nums1[i])                {Res.push_back (nums1[i]); }                ++i; ++J; }        }        returnRes; }};

Solution Three:

classSolution { Public:    /** * @param nums1 an integer array * @param nums2 a integer array * @return an integer array*/Vector<int> Intersection (vector<int>& Nums1, vector<int>&nums2) {        Set<int>Res;        Sort (Nums2.begin (), Nums2.end ());  for(Auto a:nums1) {if(BinarySearch (NUMS2, a)) {Res.insert (a); }        }        returnvector<int>(Res.begin (), Res.end ()); }    BOOLBinarySearch (vector<int> &nums,inttarget) {        intleft =0, right =nums.size ();  while(Left <Right ) {            intMid = left + (right-left)/2; if(Nums[mid] = = target)return true; Else if(Nums[mid] < target) left = mid +1; Elseright =mid; }        return false; }};

Solution Four:

classSolution { Public:    /** * @param nums1 an integer array * @param nums2 a integer array * @return an integer array*/Vector<int> Intersection (vector<int>& Nums1, vector<int>&nums2) {        Set<int>S1 (Nums1.begin (), Nums1.end ()), S2 (Nums2.begin (), Nums2.end ()), res;        Set_intersection (S1.begin (), S1.end (), S2.begin (), S2.end (), Inserter (res, Res.begin ())); returnvector<int>(Res.begin (), Res.end ()); }};

[Lintcode] Intersection of two Arrays two arrays intersect