A11081. Odds and Ends
编程题
普及/提高-
知识点
题目描述
Where do odds begin, and where do they end? Where does hope emerge, and will they ever break?
Given an integer sequence $a_{1},a_{2},...,a_{n}$ of length $n$ . Decide whether it is possible to divide it into an odd number of non-empty subsegments, the each of which has an odd length and begins and ends with odd numbers.
A subsegment is a contiguous slice of the whole sequence. For example, ${3,4,5}$ and ${1}$ are subsegments of sequence ${1,2,3,4,5,6}$ , while ${1,2,4}$ and ${7}$ are not.
Given an integer sequence $a_{1},a_{2},...,a_{n}$ of length $n$ . Decide whether it is possible to divide it into an odd number of non-empty subsegments, the each of which has an odd length and begins and ends with odd numbers.
A subsegment is a contiguous slice of the whole sequence. For example, ${3,4,5}$ and ${1}$ are subsegments of sequence ${1,2,3,4,5,6}$ , while ${1,2,4}$ and ${7}$ are not.
输入格式
The first line of input contains a non-negative integer $n$ ( $1<=n<=100$ ) — the length of the sequence.
The second line contains $n$ space-separated non-negative integers $a_{1},a_{2},...,a_{n}$ ( $0<=a_{i}<=100$ ) — the elements of the sequence.
The second line contains $n$ space-separated non-negative integers $a_{1},a_{2},...,a_{n}$ ( $0<=a_{i}<=100$ ) — the elements of the sequence.
输出格式
Output "Yes" if it's possible to fulfill the requirements, and "No" otherwise.
You can output each letter in any case (upper or lower).
You can output each letter in any case (upper or lower).
输入输出样例
输入 #1
3 1 3 5
输出 #1
Yes
输入 #2
5 1 0 1 5 1
输出 #2
Yes
输入 #3
3 4 3 1
输出 #3
No
输入 #4
4 3 9 9 3
输出 #4
No
说明/提示
In the first example, divide the sequence into $1$ subsegment: ${1,3,5}$ and the requirements will be met.
In the second example, divide the sequence into $3$ subsegments: ${1,0,1}$ , ${5}$ , ${1}$ .
In the third example, one of the subsegments must start with $4$ which is an even number, thus the requirements cannot be met.
In the fourth example, the sequence can be divided into $2$ subsegments: ${3,9,9}$ , ${3}$ , but this is not a valid solution because $2$ is an even number.
In the second example, divide the sequence into $3$ subsegments: ${1,0,1}$ , ${5}$ , ${1}$ .
In the third example, one of the subsegments must start with $4$ which is an even number, thus the requirements cannot be met.
In the fourth example, the sequence can be divided into $2$ subsegments: ${3,9,9}$ , ${3}$ , but this is not a valid solution because $2$ is an even number.