Submission #1011775

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011775		dimashhh	Permutation (APIO22_perm)	C++17	96.67 / 100	791 ms	600 KiB

perm

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

ll dp[150],t[150];
ll K;
int n;
void upd(int pos,ll val){
	while(pos <= n){
		t[pos] += val;
		pos += pos & -pos;
	}
}
ll sum(int p){
	ll ret = 0;
	while(p > 0){
		ret += t[p];
		p -= (p & -p);
	}
	return ret;
}
ll sum(int l,int r){
	return sum(r) - sum(l - 1);
}
ll calc(vector<int> &x){
	ll S = 1;
	n = (int)x.size();
	for(int i = 0;i < n;i++){
		t[i+1] =0 ;
	}
	for(int i = 0;i < (int)x.size();i++){
		dp[i] = 1 + sum(1,x[i]);
		S += dp[i];
		if(S > K) return K + 1;
		upd(x[i]+1,dp[i]);
	}
	return S;
}
vector<int> ins(vector<int> &x,int a){
	vector<int> ret = x;
	for(int i = 0;i < (int)ret.size();i++){
		if(ret[i] >= a){
			ret[i]++;
		}
	}
	ret.push_back(a);
	return ret;
}
vector<int> solve(ll k,ll G,vector<int> a){
	ll it = 3;
	while(G * it <= k){
		G *= it;
		int m = (int)a.size();
		for(int j = m + it - 2;j >= m;j--){
			a.push_back(j);
		}
	}
	while(G != k){
		ll mx = -1;
		int pos;
		vector<pair<int,int>> tt;
		vector<int> t;
		for(int j = 0;j < (int)a.size();j++){
			tt.push_back({a[j],j});
			t.push_back(a[j] + 1);
		}
		sort(tt.begin(),tt.end());
		t.push_back(0);
		for(int i = 0;i <= (int)a.size();i++){
			ll val = calc(t);	
			if(val <= k){
				if(val > mx){
					mx = val;
					pos = i;
				}
			}else break;
			t.pop_back();
			t.push_back(i + 1);
			if(i != (int)a.size()){
				t[tt[i].second]--;
			}
		}
		G = mx;
		a = ins(a,pos);
	}
	return a;
}
vector<int> construct_permutation(long long k)
{
	K = k;
	vector<int> ret;
	if(k == 1) return ret;
	auto upd = [&](vector<int> f){
		if((int)ret.size() > (int)f.size()){
			ret = f;
		}
	};
	ret = solve(k,1ll,vector<int>());
	vector<int> f(4);
	iota(f.begin(),f.end(),0);
	int it = 0;
	do{
		if(it > 12) break;
		it++;
		ll G = calc(f);
		if(G <= k){
			upd(solve(k,G,f));
		}
	}while(next_permutation(f.begin(),f.end()));
	return ret;
}

Compilation message (stderr)

perm.cpp: In function 'std::vector<int> solve(ll, ll, std::vector<int>)':
perm.cpp:86:16: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   86 |   a = ins(a,pos);
      |                ^

• Subtask 1: 10 / 10
• Subtask 2: 86.66666667 / 90