在2d向量的特定位置插入 [英] Insert at specific location of a 2d vector

问题描述

我有一个2d向量，代表一个2d网格;因此 grid [0] [2] 。我需要插入 - 这里不是正确的词。在特定位置的向量说 grid [3] [2] 将会有 grid [0] [0] 但是当需要 insert 到 grid [3] 2] 除了 grid [0] [0] 之前可能没有任何东西，并且需要在之间的空格。有任何方法吗？

I have a 2d vector which represents a 2d grid; so grid[0][2] for example. I am needing to 'insert' -might not be the right word here. a vector at a specific location say grid[3][2] there will definitely be a grid[0][0] but when im needing to insert into grid[3][2] there may be nothing before it other than grid[0][0] and there needs to be the space in between for later on. Is there any way to do this?

感谢您的帮助。

ps：I应该注意向量的大小是未知的（它们将随时间增长）。

ps: I should note that the size of the vectors are not known (they will grow over time)

推荐答案

不确定我是否正确理解您的要求，但：

I'm not sure if I understand your requirements correctly, but:

std::vector<std::vector<int>> grid(4);  // 4 rows

grid[3].resize(3)  // resize 4th row

grid[3][2] = 42;

您的2D网格会像这样看起来：

Your 2D grid would then "look" like that:

 |
 - 
 |
 -                  <---  3 empty rows
 |
 --------------
 | 0 | 0 | 42 |
 --------------

稍后调整行大小。注意，有0行，但还没有[0] [0]元素，你必须自己添加。

You can freely resize the rows later on. Note that there is row 0, but no [0][0] element just yet, you have to add it yourself.

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