2022. Convert 1D Array Into 2D Array
这次算简单，
但是要判断无法建立 2D array 的要求满多余的。
练习用 iterator 写写看
class Solution {
public:
vector<vector<int>> construct2DArray(vector<int>& original, int m, int n)
{
if (original.size() != m * n) {
return vector<vector<int>>();
}
vector<vector<int>> result;
for (int i = 0; i < m; i++) {
int startIndex = i * n;
int endInex = (i + 1) * n; // exclusive index
vector<int> subArray(next(original.cbegin(), startIndex),
next(original.cbegin(), endInex));
result.emplace_back(subArray);
}
return result;
}
};