Frequency map concept || JAVA || Easy Undestanding :)
Create the frequency map of the integers present in the matrix.\n2. the ans will be the index which has the count equals to the length of the matrix\n\n\nclass 
1. Create the frequency map of the integers present in the matrix.\n2. the ans will be the *index which has the count equals to the length of the matrix*\n\n```\nclass Solution {\n    public List<Integer> intersection(int[][] nums) {\n        List<Integer> ans = new ArrayList<>();\n        int[] frequencyMap = new int[1001];\n        \n        for(int[] arr: nums){\n            for(int x:arr){\n                frequencyMap[x]++;\n            }\n        }\n        \n        for(int i=0; i< frequencyMap.length; i++){\n            if(frequencyMap[i] == nums.length){\n                ans.add(i);\n            }\n        }\n        \n        return ans;\n    }\n}\n```
['Java']