A15079 | Directional Increase
时间限制1s
内存限制256MB
通过 / 提交0/0
题目描述
We have an array of length $n$ . Initially, each element is equal to $0$ and there is a pointer located on the first element.
We can do the following two kinds of operations any number of times (possibly zero) in any order:
1. If the pointer is not on the last element, increase the element the pointer is currently on by $1$ . Then move it to the next element.
2. If the pointer is not on the first element, decrease the element the pointer is currently on by $1$ . Then move it to the previous element.
But there is one additional rule. After we are done, the pointer has to be on the first element.
You are given an array $a$ . Determine whether it's possible to obtain $a$ after some operations or not.
We can do the following two kinds of operations any number of times (possibly zero) in any order:
1. If the pointer is not on the last element, increase the element the pointer is currently on by $1$ . Then move it to the next element.
2. If the pointer is not on the first element, decrease the element the pointer is currently on by $1$ . Then move it to the previous element.
But there is one additional rule. After we are done, the pointer has to be on the first element.
You are given an array $a$ . Determine whether it's possible to obtain $a$ after some operations or not.
输入格式
The first line contains a single integer $t$ $(1\le t\le 1000)$ — the number of test cases. The description of the test cases follows.
The first line of each test case contains a single integer $n$ $(1\le n\le 2 \cdot 10^5)$ — the size of array $a$ .
The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ( $-10^9 \le a_i \le 10^9$ ) — elements of the array.
It is guaranteed that the sum of $n$ over all test cases doesn't exceed $2 \cdot 10^5$ .
The first line of each test case contains a single integer $n$ $(1\le n\le 2 \cdot 10^5)$ — the size of array $a$ .
The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ( $-10^9 \le a_i \le 10^9$ ) — elements of the array.
It is guaranteed that the sum of $n$ over all test cases doesn't exceed $2 \cdot 10^5$ .
输出格式
For each test case, print "Yes" (without quotes) if it's possible to obtain $a$ after some operations, and "No" (without quotes) otherwise.
You can output "Yes" and "No" in any case (for example, strings "yEs", "yes" and "Yes" will be recognized as a positive response).
You can output "Yes" and "No" in any case (for example, strings "yEs", "yes" and "Yes" will be recognized as a positive response).
输入输出样例
输入 #1
7 2 1 0 4 2 -1 -1 0 4 1 -4 3 0 4 1 -1 1 -1 5 1 2 3 4 -10 7 2 -1 1 -2 0 0 0 1 0
输出 #1
No Yes No No Yes Yes Yes
In the first test case we can obtain the array after some operations, but the pointer won't be on the first element.
One way of obtaining the array in the second test case is shown below.
$\langle \underline{0}, 0, 0, 0\rangle \to \langle 1, \underline{0}, 0, 0 \rangle \to \langle \underline{1}, -1, 0, 0\rangle \to \langle 2, \underline{-1}, 0, 0\rangle \to \langle 2, 0, \underline{0}, 0\rangle \to \langle 2, \underline{0}, -1, 0\rangle \to \langle \underline{2}, -1, -1, 0\rangle$
One way of obtaining the array in the second test case is shown below.
$\langle \underline{0}, 0, 0, 0\rangle \to \langle 1, \underline{0}, 0, 0 \rangle \to \langle \underline{1}, -1, 0, 0\rangle \to \langle 2, \underline{-1}, 0, 0\rangle \to \langle 2, 0, \underline{0}, 0\rangle \to \langle 2, \underline{0}, -1, 0\rangle \to \langle \underline{2}, -1, -1, 0\rangle$
C++ 编辑器
输入
输出
可保存默认模板;新题优先使用已保存模板。
当前快捷键仅展示,暂不支持修改。
- 撤销
Ctrl / ⌘ + Z - 重做
Ctrl / ⌘ + Y - 查找
Ctrl / ⌘ + F - 全选
Ctrl / ⌘ + A - 复制
Ctrl / ⌘ + C - 剪切
Ctrl / ⌘ + X - 粘贴
Ctrl / ⌘ + V - 自动排版
工具栏排版按钮 - 草稿保存
编辑时自动保存到本机
历史
提交记录
状态说明时间源码
AI
作答助手
你好,我是作答助手。可以问思路、复杂度、样例含义或代码报错原因;不会直接给出完整 AC 代码。
确定要清空代码吗?
提交通过
评测结果:Accepted