将二维数组中每一行的空元素移动到该行的末尾 [英] Move null elements of each row in a 2D array to the end of that row

问题描述

假设我有一个看起来像这样的二维数组:

Let's say I have a 2d array which looks like this:

[[O, X, null, O, O, null, null], [null, null, O, null, null, O, O]]

我希望它看起来像这样:

And I want it to look like this:

[[O, X, O, O, null, null, null], [O, O, O, null, null, null, null]]

我试过了，但它不起作用:

I tried this, but it's not working:

String[][] a = new String[row][col];
String[][] b = new String[row][col];

for (int i = 0; i < a.length; i++) {
    for (int j = 0; j < a.length; j++) {
        if (a[i][j] != null) {
            a[i][j] = b[i][j];
        } else {
            b[i][j] = a[i][j + 1];
        }
    }
}

推荐答案

解决问题的几点

• 您需要使用 a[i].length 进行内循环
• a[i][j] = b[i][j];这里你需要在b中赋值a
• 您需要为 b 2D 数组的每一行使用计数器索引，并且每当发现非空值时，在存储后增加此值，其余索引默认为空值.

• You need to use a[i].length for inner loop
• a[i][j] = b[i][j]; here you need to assign a value in b
• You need to use a counter index for b 2D array's every row and whenever found not-null increment this after storing and remaining index are by defult null.

for (int i = 0; i < a.length; i++) {
  int indNew = 0; // Index for every row
  for (int j = 0; j < a[i].length; j++) {
    if (a[i][j] != null) {
      b[i][indNew] = a[i][j]; // store not null value
      indNew++;  // increase after storing
    }
  }
}

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