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 kdistinct 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:
- The
nandkare in the range 1 <= k < n <= 104.
Runtime: 28 ms, faster than 39.80% of C++ online submissions for Beautiful Arrangement II.
构造题
最小，k=1是顺序或者倒序的排列。
最大，k=n-1是依此从两头挑数的排列。
根据k来判断要排多少个头尾数。
#include <vector>
#include <iostream>
using namespace std;
class Solution {
public:
vector<int> constructArray(int n, int k) {
int tmp = k/;
vector<int> ret;
int idx = ;
while(tmp){
ret.push_back(idx);
ret.push_back(n+ - idx);
idx++;
tmp--;
}
if(k % == ){
for(int i = idx; i<= n+-idx; i++) ret.push_back(i);
}else for(int i=n+-idx; i>=idx; i--) ret.push_back(i);
return ret;
}
};