// you can also use imports, for example:
 import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int[][] vectorToMatrix(int[] A) {
        int dim = (int) sqrt(A.length);
        
        int[][] result = new int[dim][dim];
        
        for (int i = 0; i < A.length; i++) {
           result[i / dim][i % dim] = A[i];
        }

        return result;
    }
    
    public int solution(int[] A) {
        int [][] matrix = vectorToMatrix(A); 
        //..
    }
}