2022. Convert 1D Array Into 2D Array.java

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