CF1375C.Element Extermination

普及/提高-

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题目描述

You are given an array aa of length nn , which initially is a permutation of numbers from 11 to nn . In one operation, you can choose an index ii ( 1i<n1 \leq i < n ) such that ai<ai+1a_i < a_{i + 1} , and remove either aia_i or ai+1a_{i + 1} from the array (after the removal, the remaining parts are concatenated).

For example, if you have the array [1,3,2][1, 3, 2] , you can choose i=1i = 1 (since a1=1<a2=3a_1 = 1 < a_2 = 3 ), then either remove a1a_1 which gives the new array [3,2][3, 2] , or remove a2a_2 which gives the new array [1,2][1, 2] .

Is it possible to make the length of this array equal to 11 with these operations?

输入格式

The first line contains a single integer tt ( 1t21041 \leq t \leq 2 \cdot 10^4 ) — the number of test cases. The description of the test cases follows.

The first line of each test case contains a single integer nn ( 2n31052 \leq n \leq 3 \cdot 10^5 ) — the length of the array.

The second line of each test case contains nn integers a1a_1 , a2a_2 , ..., ana_n ( 1ain1 \leq a_i \leq n , aia_i are pairwise distinct) — elements of the array.

It is guaranteed that the sum of nn over all test cases doesn't exceed 31053 \cdot 10^5 .

输出格式

For each test case, output on a single line the word "YES" if it is possible to reduce the array to a single element using the aforementioned operation, or "NO" if it is impossible to do so.

输入输出样例

  • 输入#1

    4
    3
    1 2 3
    4
    3 1 2 4
    3
    2 3 1
    6
    2 4 6 1 3 5

    输出#1

    YES
    YES
    NO
    YES

说明/提示

For the first two test cases and the fourth test case, we can operate as follow (the bolded elements are the pair chosen for that operation):

[1,2,3][1,2][1][\text{1}, \textbf{2}, \textbf{3}] \rightarrow [\textbf{1}, \textbf{2}] \rightarrow [\text{1}]

[3,1,2,4][3,1,4][3,4][4][\text{3}, \textbf{1}, \textbf{2}, \text{4}] \rightarrow [\text{3}, \textbf{1}, \textbf{4}] \rightarrow [\textbf{3}, \textbf{4}] \rightarrow [\text{4}]

[2,4,6,1,3,5][4,6,1,3,5][4,1,3,5][4,1,5][4,5][4][\textbf{2}, \textbf{4}, \text{6}, \text{1}, \text{3}, \text{5}] \rightarrow [\textbf{4}, \textbf{6}, \text{1}, \text{3}, \text{5}] \rightarrow [\text{4}, \text{1}, \textbf{3}, \textbf{5}] \rightarrow [\text{4}, \textbf{1}, \textbf{5}] \rightarrow [\textbf{4}, \textbf{5}] \rightarrow [\text{4}]

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