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No.2812 Plus Minus Blackboard

レベル : / AI推定難易度 : 1325 / 実行時間制限 : 1ケース 2.000秒 / メモリ制限 : 512 MB / 標準ジャッジ問題
タグ : （AC するまで非表示） / 解いたユーザー数 85
作問者 : Yoyoyo8128 / テスター : hirayuu_yc Magentor warabi0906 highlighter zeta7532
お気に入りにしたユーザー ProblemId : 11004 / 自分の提出
問題文最終更新日: 2024-07-19 21:19:28
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yukicoder contest 437 ('09 Contest 002 day2) (順位表) の他の問題:

Problem Statement

You are given an integer sequence $A=(A_1,A_2,\dots,A_N)$ of length $N$.

You may perform the following operation any number of times.

  • Choose a pair $(i,j)$ of distinct integers between $1$ and $|A|$, inclusive. Here, $A_i\leq 0$ ,$A_j\geq 0$ must hold. Append $A_i+A_j$ to the end of $A$, and then simultaneously delete the $i$-th and $j$-th elements from $A$.

Determine whether it is possible to make the number of elements of $A$ equal to $1$.

Constraints

  • $1\leq N\leq 2\times 10^5$
  • $-10^9\leq A_i\leq 10^9$
  • All input values are integers.

Input

$N$
$A_1\ A_2\dots A_N$

Output

Print Yes if the number of elements of $A$ can be made equal to $1$, and No otherwise.

Sample

Sample 1
Input
2
3 5
Output
No

The operation cannot be performed with either $i=1,j=2$ or $i=2,j=1$.

Sample 2
Input
3
-45 8 10
Output
Yes

The goal can be achieved as follows.

  • Perform the operation with $i=1,j=2$. $A=(10,-37)$ results.
  • Perform the operation with $i=2,j=1$. $A=(-27)$ results.

Sample 3
Input
5
-1000000000 -100000000 -10000000 -1000000 1000000000
Output
Yes

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