Submission #960511

#	Time	Username	Problem	Language	Result	Execution time	Memory
960511		vjudge1	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	279 ms	29952 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
#define ll long long

using namespace std;

#define all(v) v.begin(),v.end()
#define pb push_back

struct FWT{
	vector<ll> bit;

	FWT(ll n){
		bit.resize(n + 69);
	}

	ll lsb(ll i){
		return (-i) & i;
	}

	void modify(ll i,ll v){
		for(i++;i<bit.size();i += lsb(i))bit[i] += v;
	}

	ll query(ll i){
		ll ans = 0;
		for(i++;i;i -= lsb(i))ans += bit[i];
		return ans;
	}
};

ll count_swaps(vector<int> A) {
	ll n = A.size();

	map<ll,vector<ll> > ind;

	for(ll i = 0;i<n;i++)ind[A[i]].pb(i);
	for(auto &u : ind)reverse(u.second.begin(), u.second.end());
	ll o[n];
	memset(o, -1, sizeof o);
	for(ll i = 0;i<n;i++){
		if(o[i] != -1)continue;
		if(A[i] < 0){
			o[i] = 2 * i + 1;
			o[ind[-A[i]].back()] = 2 * i + 2;
		}else{
			o[i] = 2 * i + 2;
			o[ind[-A[i]].back()] = 2 * i + 1;
		}
		ind[A[i]].pop_back();
		ind[-A[i]].pop_back();
	} 
	ll ans = 0;

	FWT fwt(2 * n);

	for(ll i = n-1;i>=0;i--){
		ans += fwt.query(o[i] - 1);
		fwt.modify(o[i], 1);
	}

	return ans;
}
  

Compilation message (stderr)

shoes.cpp: In member function 'void FWT::modify(long long int, long long int)':
shoes.cpp:22:12: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |   for(i++;i<bit.size();i += lsb(i))bit[i] += v;
      |           ~^~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15