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, $v_l, v_{l + 1}, \dots, v_r$.
Input
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 $10^5$.
Output
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.
Example
input
3 2 1 3 3 3 6 99995 9998900031 9998900031
output
1 2 1 1 3 2 3 1
Note
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 $1$.
Solution:
#include <bits/stdc++.h> using namespace std; #define rep(i,a,n) for (int i=a;i<n;i++) #define per(i,a,n) for (int i=n-1;i>=a;i--) #define pb push_back #define mp make_pair #define all(x) (x).begin(),(x).end() #define fi first #define se second #define SZ(x) ((int)(x).size()) typedef vector<int> VI; typedef long long ll; typedef pair<int,int> PII; typedef double db; mt19937 mrand(random_device{}()); const ll mod=1000000007; int rnd(int x) { return mrand() % x;} ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;} ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;} // head const int N=101000; int _,n; ll l,r,s[N]; int calc(ll x) { if (x>s[n-1]) return 1; auto a=lower_bound(s+1,s+n,x)-s; int b=x-s[a-1]; if (b%2==1) return a; else return b/2+a; } int main() { for (scanf("%d",&_);_;_--) { scanf("%d%lld%lld",&n,&l,&r); rep(i,1,n+1) s[i]=s[i-1]+2*(n-i); for (ll i=l;i<=r;i++) printf("%d ",calc(i)); puts(""); } }