2022. Convert 1D Array Into 2D Array

You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with m rows and n columns using all the elements from original.

The elements from indices 0 to n - 1 (inclusive) of original should form the first row of the constructed 2D array, the elements from indices n to 2 * n - 1 (inclusive) should form the second row of the constructed 2D array, and so on.

Return an m x n 2D array constructed according to the above procedure, or an empty 2D array if it is impossible.

class Solution {
public:
    vector<vector<int>> construct2DArray(vector<int>& original, int m, int n) {
        if(m * n != original.size()) return {};
        vector<vector<int>> res(m, vector<int>(n));
        for(int i = 0; i < original.size(); i++) {
            res[i/n][i%n] = original[i];
        }
        return res;
    }
};