Lucky numbers in the [leetcode daily question] matrix

The lucky number in the matrix
difficulty ： Simple

The minimum value of each line of the record is traversed for the first time , Deposit in set Collection . The second traversal records the maximum value of each column , Deposit in set Collection , When deposit fails , That is, the current element conforms to the rule of lucky number .
The code is as follows ：

	 public List<Integer> luckyNumbers (int[][] matrix) {
    
        List<Integer> res = new ArrayList<>();
        Set<Integer> set = new HashSet<>();
        int m = matrix.length;
        int n = matrix[0].length;
        for (int i = 0; i < m; i++) {
    
            int tmp = Integer.MAX_VALUE;
            for (int j = 0; j < n; j++) {
    
                tmp = Math.min(tmp,matrix[i][j]);
            }
            set.add(tmp);
        }

        for (int i = 0; i < n; i++) {
    
            int tmp = Integer.MIN_VALUE;
            for (int j = 0; j < m; j++) {
    
                tmp = Math.max(tmp,matrix[j][i]);
            }
            if (!set.add(tmp)){
    
                res.add(tmp);
            }
        }
        return res;
    }

Execution results ： success