problem:Given three Sorted arrays in non-decreasing order, print all common elements in these arrays.
solution suggests declaring 3 vars i,j and k for every array and to increment them only when the element is a minimum. But why not incrementing it anyways, as long as the element is not the maximum?!

correct solution

ArrayList<Integer> commonElements(int A[], int B[], int C[], int n1, int n2, int n3) 
    {
        // Initialize three pointers for each array
        int i = 0, j = 0, k = 0;
    
        // Initialize an arraylist to store the common elements
        ArrayList<Integer> res = new ArrayList<Integer>();
    
        // Initialize a variable to store the last checked element
        int last = Integer.MIN_VALUE;

        // Loop until any of the three arrays reaches its end
        while (i < n1 && j < n2 && k < n3)
        {
        // If the current elements of all three arrays are equal and not the same as the last checked element
            if (A[i] == B[j] && A[i] == C[k] && A[i] != last) 
            {
            // Add the common element to the result arraylist
                res.add (A[i]);
            
            // Update the last checked element
                last = A[i];
            
            // Move to the next element in each array
                i++;
                j++;
                k++;
        }
        // If the current element of array A is the smallest, move to the next element in array A
            else if (Math.min (A[i], Math.min(B[j], C[k])) == A[i]) i++;
        // If the current element of array B is the smallest, move to the next element in array B
            else if (Math.min (A[i], Math.min(B[j], C[k])) == B[j]) j++;
        // If the current element of array C is the smallest, move to the next element in array C
            else k++;
    }

my solution

public static ArrayList<Integer> commonElements(int A[], int B[], int C[], int n1, int n2, int n3)
    {
        // code here
        ArrayList <Integer> res=new ArrayList <Integer>();
        int i=0;
        int j=0;
        int k=0;
        long last=Long.MIN_VALUE;
        while(i<n1 && j<n2 && k<n3){

            if(A[i]==B[j] && B[j]==C[k] && A[i]!=last){
                res.add(A[i]);
                last=A[i];
                i++;
                j++;
                k++;

            }else if(A[i]!=Math.max(A[i],Math.max(B[j],C[k]))){
                i++;
            }else if(B[j]!=Math.max(A[i],Math.max(B[j],C[k]))){
                j++;
            }else if( C[k]!=Math.max(A[i],Math.max(B[j],C[k]))){
                k++;
            }
        }
        return res;
    }