Convert 1D Array Into 2D Array

给一个一维数组和整数m和n, 变成二维数组[m][n];

class Solution {
    public int[][] construct2DArray(int[] original, int m, int n) {
        int[][] res = new int[m][n];
        if(m*n != original.length)
            return new int[][]{};
        int p = 0;
        for(int i = 0; i < m; i++){
            for(int j = 0; j < n; j++){
                res[i][j] = original[p++];
            }
        }
        return res;
    }
}