Flatten a 2D Array

Combine the rows of a 2D integer array into one array. Read rows from top to bottom and integers within each row from left to right. Skip empty rows. Preserve repeated integers and their order. Rows may have different lengths. There are exactly two array levels: rows contain only integers, with no null values or deeper lists.

Implement flatten_nested_list(values).

Input

values: The integer rows to combine, in order.

Output

Return all integers in row order. Return an empty array if there are no integers.

制約

0 ≤ number of rows ≤ 10,000. At most 10,000 integers in total. Each integer is between −1,000,000,000 and 1,000,000,000. Rows may be empty or have different lengths.

例

入力：
values = [
    [1, 2],
    [],
    [3, 4]
]

期待される出力：
expected = [1, 2, 3, 4]

入力：
std::vector<std::vector<long long>> values = {
    {1, 2},
    {},
    {3, 4}
};

期待される出力：
std::vector<long long> expected = {1, 2, 3, 4};

入力：
long[][] values = new long[][] {
    new long[] {1, 2},
    new long[] {},
    new long[] {3, 4}
};

期待される出力：
long[] expected = new long[] {1, 2, 3, 4};

入力：
values = [
    [],
    []
]

期待される出力：
expected = []

入力：
std::vector<std::vector<long long>> values = {
    {},
    {}
};

期待される出力：
std::vector<long long> expected = {};

入力：
long[][] values = new long[][] {
    new long[] {},
    new long[] {}
};

期待される出力：
long[] expected = new long[] {};

参考資料

この課題はCodeUtility用に調整されています。上記の説明と制約に従ってください。

• Exercism: Flatten Array