350. Intersection of Two Arrays II（LeetCode）

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

Example:
Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2].

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?

  class Solution {
  public:
      vector<int> intersect(vector<int>& nums1, vector<int>& nums2) {
          sort(nums1.begin(), nums1.end());
          sort(nums2.begin(), nums2.end());
          int len1 = nums1.size();
          int len2 = nums2.size();
          
          int i = 0;
          int j = 0;
          vector<int> vet;
          while (i < len1&&j < len2)
          {
              if (nums1[i] == nums2[j])
              {
                  vet.push_back(nums1[i]);
                  i++;
                  j++;
              
              }
              else
              {
                  if (nums1[i] < nums2[j])
                  {
                      i++;
                  }
                  else
                  {
                      j++;
                  }
              }
          }
          return vet;
      }
  };