Problem
Given two arrays, write a function to compute their intersection.
Note:
- Each element in the result should appear as many times as it shows in both arrays.
- The result can be in any order.
Follow up:
- What if the given array is already sorted? How would you optimize your algorithm?
- What if nums1's size is small compared to nums2's size? Which algorithm is better?
- What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?
Example
Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2,2]
Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [4,9]
Code
static int var =[](){
std::ios::sync_with_stdio(false);
cin.tie(NULL);
return 0;
}();
class Solution {
public:
vector<int> intersect(vector<int>& nums1, vector<int>& nums2) {
sort(nums1.begin(),nums1.end());
sort(nums2.begin(),nums2.end());
int i=0,j=0;
vector<int> res;
while(i<nums1.size() && j<nums2.size()){
if(nums1[i]==nums2[j]){
res.push_back(nums1[i]);
i++;
j++;
}
else if(nums1[i]<nums2[j])
i++;
else
j++;
}
return res;
}
};
Result
350. Intersection of Two Arrays II.png
