说明:我无法理解我的老师.
问题:
Write a method called
printSquare
that takes in two integer
parameters,amin
and amax
,and prints the numbers in the range from
min
tomax
inclusive in a square pattern. The square pattern is
easier to understand by example than by explanation,so take a look at
the sample method calls and their resulting console output in the
table below. Each line of the square consists of a circular sequence
of increasing integers betweenmin
andmax
. Each line prints a
different permutation of this sequence. The first line begins with
min,the second line begins withmin + 1
,and so on. When the
sequence in any line reachesmax
,it wraps around back tomin
. You
may assume the caller of the method will pass amin
and amax
parameter such thatmin
is less than or equal tomax
我不能为我的生活弄清楚如何使数字停在’max’值并从线的中间重新开始.
这是我到目前为止,道歉,但我遇到for循环的问题.
for(int i = 0; i < row; i++) { for(int d = 0; d < row; d++) { System.out.print(d+1); } System.out.println(i); }
我知道我使用了两次行,但它是我可以让编译器用循环形成方形的唯一方法.有人甚至远程了解我想要做什么吗? :/
解决方法
int side = to - from + 1; /// the size/width of the square.
square(row,col)中任意一点的值为:
from + ((row + col) % side)
你应该能够把它放在你的循环中并“吸烟”.
根据评论要求解释进行编辑.
诀窍是循环遍历’矩阵’中的所有位置.鉴于矩阵是方形的,循环相对简单,只有两个遍历系统的循环(嵌套):
final int side = to - from + 1; for (int row = 0; row < side; row++) { for(int col = 0; col < side; col++) { ... magic goes here.... } }
现在,在这个循环中,我们有变量row和col,它们代表我们感兴趣的矩阵中的单元格.该单元格中的值需要与它与原点的距离成正比…..让我解释一下….如果原点是左上角(它是),那么与原点的距离是:
0 1 2 3 4 1 2 3 4 5 2 3 4 5 6 3 4 5 6 7 4 5 6 7 8
距离是行和列的总和……(行和列从0开始计数).
我们在每个矩阵中放置的值仅限于固定范围.对于上面的示例,使用大小为5的正方形,可以将其指定为printSquare(1,5).
每个单元格中的值是from值(本例中为1)加上距离原点的距离…天真地看起来像:
1 2 3 4 5 2 3 4 5 6 3 4 5 6 7 4 5 6 7 8 5 6 7 8 9
在这里,单元格中的值已超过5的限制,我们需要将它们包裹起来…所以,诀窍是“包裹”距离原点的距离…..并且“模数”运算符很棒为了那个原因.首先,考虑原始的“原点距离”矩阵:
0 1 2 3 4 1 2 3 4 5 2 3 4 5 6 3 4 5 6 7 4 5 6 7 8
如果我们用“除以5的剩余距离”(模5或%5)来填充此矩阵,我们得到矩阵:
0 1 2 3 4 1 2 3 4 0 2 3 4 0 1 3 4 0 1 2 4 0 1 2 3
现在,如果我们将这个’modulo’结果添加到from值(1),我们得到我们的最终矩阵:
1 2 3 4 5 2 3 4 5 1 3 4 5 1 2 4 5 1 2 3 5 1 2 3 4
从某种意义上说,你需要知道的是每个单元格的值是:
the from value plus the remainder when you divide the 'distance' by the width.
这是我测试过的代码:
public static final String buildSquare(final int from,final int to) { final StringBuilder sb = new StringBuilder(side * side); final int side = to - from + 1; for (int row = 0; row < side; row++) { for(int col = 0; col < side; col++) { sb.append( from + ((row + col) % side) ); } sb.append("\n"); } return sb.toString(); } public static void main(String[] args) { System.out.println(buildSquare(1,5)); System.out.println(buildSquare(3,9)); System.out.println(buildSquare(5,5)); System.out.println(buildSquare(0,9)); System.out.println(buildSquare(0,3)); }