# 667. Beautiful Arrangement II

Given two integers `n` and `k`, you need to construct a list which contains `n` different positive integers ranging from `1` to `n` and obeys the following requirement:
Suppose this list is [a1, a2, a3, … , an], then the list [|a1 - a2|, |a2 - a3|, |a3 - a4|, … , |an-1 - an|] has exactly `k` distinct integers.

If there are multiple answers, print any of them.

Example 1:

``````Input: n = 3, k = 1
Output: [1, 2, 3]
Explanation: The [1, 2, 3] has three different positive integers ranging from 1 to 3, and the [1, 1] has exactly 1 distinct integer: 1.
``````

Example 2:

``````Input: n = 3, k = 2
Output: [1, 3, 2]
Explanation: The [1, 3, 2] has three different positive integers ranging from 1 to 3, and the [2, 1] has exactly 2 distinct integers: 1 and 2.
``````

Note:

1. The `n` and `k` are in the range 1 <= k < n <= 104.

1, 2, 3, 4, 5, 6, 7, 8

1, 8, 2, 7, 3, 6, 4, 5

``````class Solution {
public:
vector<int> constructArray(int n, int k) {
vector<int> res;
int i = 1, j = n;
while (i <= j) {
if (k > 1) res.push_back(k-- % 2 ? i++ : j--);
else res.push_back(i++);
}
return res;
}
};
``````

``````class Solution {
public:
vector<int> constructArray(int n, int k) {
vector<int> res;
int i = 1, j = n;
while (i <= j) {
res.push_back(k > 1 ? (k-- % 2 ? i++ : j--) : i++);
}
return res;
}
};
``````

Beautiful Arrangement

https://discuss.leetcode.com/topic/101113/c-java-clean-code-4-liner

LeetCode All in One 题目讲解汇总(持续更新中…)

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