A13454. Minimum Euler Cycle
编程题
普及/提高-
知识点
题目描述
You are given a complete directed graph $K_n$ with $n$ vertices: each pair of vertices $u \neq v$ in $K_n$ have both directed edges $(u, v)$ and $(v, u)$ ; there are no self-loops.
You should find such a cycle in $K_n$ that visits every directed edge exactly once (allowing for revisiting vertices).
We can write such cycle as a list of $n(n - 1) + 1$ vertices $v_1, v_2, v_3, \dots, v_{n(n - 1) - 1}, v_{n(n - 1)}, v_{n(n - 1) + 1} = v_1$ — a visiting order, where each $(v_i, v_{i + 1})$ occurs exactly once.
Find the lexicographically smallest such cycle. It's not hard to prove that the cycle always exists.
Since the answer can be too large print its $[l, r]$ segment, in other words, $v_l, v_{l + 1}, \dots, v_r$ .
You should find such a cycle in $K_n$ that visits every directed edge exactly once (allowing for revisiting vertices).
We can write such cycle as a list of $n(n - 1) + 1$ vertices $v_1, v_2, v_3, \dots, v_{n(n - 1) - 1}, v_{n(n - 1)}, v_{n(n - 1) + 1} = v_1$ — a visiting order, where each $(v_i, v_{i + 1})$ occurs exactly once.
Find the lexicographically smallest such cycle. It's not hard to prove that the cycle always exists.
Since the answer can be too large print its $[l, r]$ segment, in other words, $v_l, v_{l + 1}, \dots, v_r$ .
输入格式
The first line contains the single integer $T$ ( $1 \le T \le 100$ ) — the number of test cases.
Next $T$ lines contain test cases — one per line. The first and only line of each test case contains three integers $n$ , $l$ and $r$ ( $2 \le n \le 10^5$ , $1 \le l \le r \le n(n - 1) + 1$ , $r - l + 1 \le 10^5$ ) — the number of vertices in $K_n$ , and segment of the cycle to print.
It's guaranteed that the total sum of $n$ doesn't exceed $10^5$ and the total sum of $r - l + 1$ doesn't exceed $10^5$ .
Next $T$ lines contain test cases — one per line. The first and only line of each test case contains three integers $n$ , $l$ and $r$ ( $2 \le n \le 10^5$ , $1 \le l \le r \le n(n - 1) + 1$ , $r - l + 1 \le 10^5$ ) — the number of vertices in $K_n$ , and segment of the cycle to print.
It's guaranteed that the total sum of $n$ doesn't exceed $10^5$ and the total sum of $r - l + 1$ doesn't exceed $10^5$ .
输出格式
For each test case print the segment $v_l, v_{l + 1}, \dots, v_r$ of the lexicographically smallest cycle that visits every edge exactly once.
输入输出样例
输入 #1
3 2 1 3 3 3 6 99995 9998900031 9998900031
输出 #1
1 2 1 1 3 2 3 1
说明/提示
In the second test case, the lexicographically minimum cycle looks like: $1, 2, 1, 3, 2, 3, 1$ .
In the third test case, it's quite obvious that the cycle should start and end in vertex $1$ .
In the third test case, it's quite obvious that the cycle should start and end in vertex $1$ .