349. Intersection of Two Arrays

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

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

Note:

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

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结果中每个元素是不同的,顺序任意

思路:排序+遍历+一个前向结果元素标志

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class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        vector<int> re;
        sort(nums1.begin(),nums1.end());
        sort(nums2.begin(),nums2.end());

        vector<int>::iterator it1 = nums1.begin();
        vector<int>::iterator it2 = nums2.begin();
        int prev = INT_MAX;
        for(;it1!=nums1.end() && it2!=nums2.end();){
            if(*it1<*it2) it1++;
            else if(*it1 > *it2) it2++;
            else{
                if(prev == *it1){
                    it1++;
                    it2++;
                    continue;
                }
                prev = *it1;
                re.push_back(*it1);
                it1++;
                it2++;
            }
        }
        return re;
    }
};