Submission #1011789

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011789		dimashhh	Permutation (APIO22_perm)	C++17	100 / 100	884 ms	852 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){
	while(G != k){
		ll mx = -1;
		int pos;
		int l = -1,r = (int)a.size() + 1;
		while(r - l > 1){
			int mid = (l + r) >> 1;
			ll val = calc(ins(a,mid));
			if(val <= k){
				pos = l = mid;
				mx = val;
			}else{
				r = mid;
			}
		}
		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(5);
	iota(f.begin(),f.end(),0);
	int it = 0;
	do{
		if(it > 50) 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:67:16: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   67 |   a = ins(a,pos);
      |                ^

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