309182: CF1638C. Inversion Graph
Memory Limit:256 MB
Time Limit:1 S
Judge Style:Text Compare
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Description
Inversion Graph
题意翻译
现在有一个序列 $p_1,p_2,\dots,p_n$,你需要构建一个无向图,规则是:当 $i < j$ 且 $p_i > p_j$ 时在 $i$ 和 $j$ 之间连一条无向边。问最后图中会有几个连通块。 Translate by CmsMartin题目描述
You are given a permutation $ p_1, p_2, \dots, p_n $ . Then, an undirected graph is constructed in the following way: add an edge between vertices $ i $ , $ j $ such that $ i < j $ if and only if $ p_i > p_j $ . Your task is to count the number of connected components in this graph. Two vertices $ u $ and $ v $ belong to the same connected component if and only if there is at least one path along edges connecting $ u $ and $ v $ . A permutation is an array consisting of $ n $ distinct integers from $ 1 $ to $ n $ in arbitrary order. For example, $ [2,3,1,5,4] $ is a permutation, but $ [1,2,2] $ is not a permutation ( $ 2 $ appears twice in the array) and $ [1,3,4] $ is also not a permutation ( $ n=3 $ but there is $ 4 $ in the array).输入输出格式
输入格式
Each test contains multiple test cases. The first line contains a single integer $ t $ ( $ 1 \le t \le 10^5 $ ) — the number of test cases. Description of the test cases follows. The first line of each test case contains a single integer $ n $ ( $ 1 \le n \le 10^5 $ ) — the length of the permutation. The second line of each test case contains $ n $ integers $ p_1, p_2, \dots, p_n $ ( $ 1 \le p_i \le n $ ) — the elements of the permutation. It is guaranteed that the sum of $ n $ over all test cases does not exceed $ 2 \cdot 10^5 $ .
输出格式
For each test case, print one integer $ k $ — the number of connected components.
输入输出样例
输入样例 #1
6
3
1 2 3
5
2 1 4 3 5
6
6 1 4 2 5 3
1
1
6
3 2 1 6 5 4
5
3 1 5 2 4
输出样例 #1
3
3
1
1
2
1