Java刷题（五）

Codewars 刷题第五天，数组问题。

Enough is enough!

Alice and Bob were on a holiday. Both of them took many pictures of the places they've been,

and now they want to show Charlie their entire collection.

However, Charlie doesn't like this sessions, since the motive usually repeats.

He isn't fond of seeing the Eiffel tower 40 times.

He tells them that he will only sit during the session if they show the same motive at most N times.

Luckily, Alice and Bob are able to encode the motive as a number.

Can you help them to remove numbers such that their list contains each number only up to N times,

without changing the order?

 

Task

Given a list lst and a number N,

create a new list that contains each number of lst at most N times without reordering.

For example if N = 2, and the input is [1,2,3,1,2,1,2,3],

you take [1,2,3,1,2], drop the next [1,2] since this would lead to 1 and 2 being in the result 3 times,

and then take 3, which leads to [1,2,3,1,2,3].

 

Example

EnoughIsEnough.deleteNth(new int[] {20,37,20,21}, 1) // return [20,37,21]

EnoughIsEnough.deleteNth(new int[] {1,1,3,3,7,2,2,2,2}, 3) // return [1, 1, 3, 3, 7, 2, 2, 2]

 题目要求：

　　给定数组，给定限制maxOccurrences,数组里的数字的出现次数不得超过限制。然后将数组返回，

对于这种不确定长度的问题还是建议使用Vector（），或者哈希表等。

此处，用到了两个函数比较巧妙getOrdefault(int,int)和Arrays.copyOfRange(int,int,int).很好的解决了遍历中的问题。