Submission #720637

#	Time	Username	Problem	Language	Result	Execution time	Memory
720637		stevancv	Permutation (APIO22_perm)	C++17	10 / 100	2 ms	340 KiB

perm

#include <bits/stdc++.h>
#include "perm.h"
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const int inf = 1e9;
ll C(ll a, ll b) {
    return (a + b - 1) / b;
}
vector<int> construct_permutation(ll k) {
    if (k <= 115) {
        vector<int> ret(k - 1);
        for (int i = 0; i < k - 1; i++) ret[i] = k - 2 - i;
        return ret;
    }
    int n = 115;
    vector<int> ret(n);
    for (int i = 0; i < n; i++) ret[i] = n - 1 - i;
    k -= n + 1;
    ll prv = n;
    for (int i = n - 1; i >= 0 && k; i--) {
        ll e = n - i; ll j = i;
        smin(j, C(k, 1ll << (e - 1)));
        if (k % (1ll << e) == 0 && j % 2 != 0) j -= 1;
        if (k % (1ll << e) != 0 && j % 2 == 0) j -= 1;
        if ((j + prv) % 2 == 0) smin(j, prv - 2);
        else smin(j, prv - 1);
        prv = j;
        for (int p = n - 1; p > n - 1 - j; p--) swap(ret[p], ret[p - 1]);
        k -= (1ll << (e - 1)) * j;
    }
    return ret;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 90