A13583. Bicolored Segments
编程题
普及/提高-
知识点
题目描述
You are given $n$ segments $[l_1, r_1], [l_2, r_2], \dots, [l_n, r_n]$ . Each segment has one of two colors: the $i$ -th segment's color is $t_i$ .
Let's call a pair of segments $i$ and $j$ bad if the following two conditions are met:
- $t_i \ne t_j$ ;
- the segments $[l_i, r_i]$ and $[l_j, r_j]$ intersect, embed or touch, i. e. there exists an integer $x$ such that $x \in [l_i, r_i]$ and $x \in [l_j, r_j]$ .
Calculate the maximum number of segments that can be selected from the given ones, so that there is no bad pair among the selected ones.
Let's call a pair of segments $i$ and $j$ bad if the following two conditions are met:
- $t_i \ne t_j$ ;
- the segments $[l_i, r_i]$ and $[l_j, r_j]$ intersect, embed or touch, i. e. there exists an integer $x$ such that $x \in [l_i, r_i]$ and $x \in [l_j, r_j]$ .
Calculate the maximum number of segments that can be selected from the given ones, so that there is no bad pair among the selected ones.
输入格式
The first line contains a single integer $n$ ( $1 \le n \le 2 \cdot 10^5$ ) — number of segments.
The next $n$ lines contains three integers $l_i, r_i, t_i$ ( $1 \le l_i \le r_i \le 10^9; t_i \in \{1, 2\}$ ) — description of the $i$ -th segment.
The next $n$ lines contains three integers $l_i, r_i, t_i$ ( $1 \le l_i \le r_i \le 10^9; t_i \in \{1, 2\}$ ) — description of the $i$ -th segment.
输出格式
Print the maximum number of segments that can be selected, so that there is no bad pair among the selected segments.
输入输出样例
输入 #1
3 1 3 1 4 6 2 2 5 1
输出 #1
2
输入 #2
5 5 8 1 1 3 2 3 4 2 6 6 1 2 10 2
输出 #2
4
输入 #3
7 19 20 1 13 15 2 6 11 2 4 10 1 14 17 1 13 13 2 5 9 1
输出 #3
5