Submission #737350

#	Time	Username	Problem	Language	Result	Execution time	Memory
737350		GrindMachine	Permutation (APIO22_perm)	C++17	91.33 / 100	2 ms	340 KiB

perm

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://codeforces.com/blog/entry/103229?#comment-917431

k <= 1e18, m <= 90:
some log k sol

think about pows of 2 and k's setbits

insert guys into perm in increasing order of val

if perm has siz = n and we insert val n (0-indexed vals) at index i (0-indexed):
it adds 2^i to the ans

*/

#include "perm.h"

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<int> construct_permutation(ll k) {
    int n = __lg(k);
    vector<int> a(n);
    rep(i, n) a[i] = i;

    int ptr = n;

    rev(bit, n - 1, 0) {
        ll f = 1ll << bit;
        if (k & f) {
            a.insert(a.begin() + bit, ptr++);
        }
    }

    return a;
}

• Subtask 1: 10 / 10
• Subtask 2: 81.333333333 / 90