Submission #987606

#	Time	Username	Problem	Language	Result	Execution time	Memory
987606		Otalp	Permutation (APIO22_perm)	C++17	100 / 100	49 ms	856 KiB

perm

#include "perm.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back


ll pref[200][200], suf[200][200];
ll a[200100];
ll n;


void calc(){
    for(int x=0; x<=n + 1; x++) pref[0][x] = 1;
    for(int i=1; i<=n; i++){
        for(int x=0; x<=n + 1; x++){
            pref[i][x] = pref[i - 1][x];
            if(a[i] <= x){
                pref[i][x] += pref[i-1][a[i]];
            }
        }
    }
    for(int x=0; x<=n + 1; x++) suf[n + 1][x] = 1;
    for(int i=n; i>=1; i--){
        for(int x=n + 1; x>=0; x--){
            suf[i][x] = suf[i + 1][x];
            if(a[i] >= x){
                suf[i][x] += suf[i + 1][a[i]];    
            }
        }
    }
}

vector<int> construct_permutation(ll k){
    n = 1;
    a[1] = 1;
    calc();
    ll g = pref[n][n];
    while(g != k){
        ll d = 0;
        ll pos, x;
        for(int i=1; i<=n + 1; i++){
            for(int j=1; j<=n+1; j++){
                ll h = pref[i - 1][j - 1] * suf[i][j];
                //cout<<i<<' '<<j<<'\n';
                //cout<<h<<'\n';
                if(h > d and h <= k - g){
                    d = h;
                    x = j;
                    pos = i;
                }
            }
        }
        //cout<<g<<' '<<pos<<' '<<x<<'\n';
        vector<int> q;
        for(int i=1; i<pos; i++){
            q.pb(a[i] + (a[i] >= x));
        }
        q.pb(x);
        for(int i=pos; i<=n; i++){
            q.pb(a[i] + (a[i] >= x));
        }
        n ++;
        for(int i=1; i<=n; i++){
            a[i] = q[i - 1];
        }
        calc();
        g = pref[n][n];
    }
    vector<int> res;
    for(int i=1; i<=n; i++) res.pb(a[i]-1);
    //for(int d: res) cout<<d<<' ';
    //cout<<'\n';
    return res;
}

Compilation message (stderr)

perm.cpp: In function 'std::vector<int> construct_permutation(long long int)':
perm.cpp:41:12: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   41 |         ll pos, x;
      |            ^~~

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