LeetCode [349] Intersection of Two Arrays

  Given two arrays, write a function to compute their intersection.

Example 1:

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2]

Example 2:

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [9,4]

Note:

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

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class Solution { public: vector<int> intersection(vector<int>& nums1, vector<int>& nums2) { set<int> st(nums1.begin(), nums1.end()); set<int> st1; for(auto n:nums2){ if(st.count(n)) st1.insert(n); } vector<int> ret(st1.begin(), st1.end()); return ret; } };

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class Solution { public: vector<int> intersection(vector<int>& nums1, vector<int>& nums2) { sort(nums1.begin(), nums1.end()); sort(nums2.begin(), nums2.end()); vector<int> ret; int i=0, j = 0, n1 = nums1.size(), n2 = nums2.size(); while(i<n1 && j<n2){ if(nums1[i]<nums2[j]) i++; else if(nums1[i]>nums2[j]) j++; else{ if(ret.empty() || ret.back()!=nums1[i]){ ret.push_back(nums1[i]); } i++; j++; } } return ret; } };