Leetcode 350) Intersection of Two Arrays II

22 Nov 2021 in Algorithms

My Solution

class Solution {
    public int[] intersect(int[] nums1, int[] nums2) {
        Map<Integer,Integer> m = new HashMap<>();
        
        for(int i=0;i<nums1.length;i++){
            if(!m.containsKey(nums1[i])){
                m.put(nums1[i],1);
            }else{
                m.put(nums1[i],m.get(nums1[i])+1);
            }
        }        
        
        List<Integer> l = new ArrayList<>();
        for(int i =0;i<nums2.length;i++){
            if(m.containsKey(nums2[i]) && m.get(nums2[i])!=0){
                l.add(nums2[i]);       
                m.put(nums2[i],m.get(nums2[i])-1);
            }
        }
        
        int[] res = new int[l.size()];
        
        int ptr=0;
        for(int i: l){
            res[ptr] = i;
            ptr++;
        }
        return res;
    }
}

Other Solution

class Solution {
    public int[] intersect(int[] nums1, int[] nums2) {


        int[] freq = new int[1000];

        ArrayList<Integer> resultList = new ArrayList<>();



        for(int i : nums2)
        {    
            freq[i]++;

        }

        for(int i: nums1)
        {
            if(freq[i]>0)
            {
                freq[i]--;
                resultList.add(i);

            }

        }

        int[] result = new int[resultList.size()];

        for(int i=0; i< resultList.size(); i++ ){
            result[i]=  resultList.get(i);              
        }
        return result;
    }
}