Submission #1200081

#	Time	Username	Problem	Language	Result	Execution time	Memory
1200081		browntoad	Permutation (APIO22_perm)	C++20	82.38 / 100	4 ms	840 KiB

perm

#include "perm.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
// #define int ll
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define REP1(i, n) FOR(i, 1, n+1)
#define RREP(i, n) for (int i = (n)-1; i >= 0; i--)
#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)((x).size())

namespace{
    const ll maxn  = 1e5+5;
    const ll mod = 1e9+7;
    const ll inf = (1ll<<60);
}

std::vector<int> construct_permutation(long long k){
	k--; // imma make it a bunch of sums

	vector<int> ret; // initially all reversed
	int cur = 0;
	for (int b = 55; b >= 0; b -= 5){
		ll tmp = (1ll<<b);
		int cnt = 0;
		while(tmp * (cnt+1) - 1 <= k){
			cnt++;
		}
		if (cnt == 0) continue;
		cnt--;

		k -= tmp * (cnt+1) - 1;

		vector<int> ra, rb;
		REP(i, b){
			ra.pb(cur++);
		}
		REP(i, cnt){
			rb.pb(cur++);
		}

		REP(i, SZ(rb)) ret.pb(rb[i]);
		RREP(i, SZ(ra)) ret.pb(ra[i]);
	}
	reverse(ALL(ret));
	return ret;
}

• Subtask 1: 10 / 10
• Subtask 2: 72.3846 / 90