Submission #826777

#	Time	Username	Problem	Language	Result	Execution time	Memory
826777		kevinsogo	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	726 ms	16720 KiB

shoes

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

struct Fen {
    vector<int> c;
    Fen(int n): c(n + 1) {}
    void inc(int i, int v = 1) {
        for (++i; i < c.size(); i += i & -i) c[i] += v;
    }
    int sum(int i, int v = 0) {
        for (; i; i -= i & -i) v += c[i];
        return v;
    }
};

ll count_swaps(vector<int> _seq) {
    vector<int> found(_seq.size() + 5);
    vector<ll> seq;
    for (int v : _seq) seq.push_back(ll(v) * _seq.size() + ((v > 0) - (v < 0)) * found[v + (_seq.size() >> 1)]++);
    unordered_map<ll,int> pos; pos.max_load_factor(0.5);
    for (int i = 0; i < seq.size(); i++) pos[seq[i]] = i;
    sort(seq.rbegin(), seq.rend(), [&](ll i, ll j) {
        int d = min(pos[i], pos[-i]) - min(pos[j], pos[-j]);
        return d ? d < 0 : i < j;
    });
    for (ll& v : seq) v = pos[v];
    ll ans = 0;
    Fen f(seq.size());
    for (ll v : seq) ans += f.sum(v), f.inc(v);
    return ans;
}

Compilation message (stderr)

shoes.cpp: In member function 'void Fen::inc(int, int)':
shoes.cpp:10:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |         for (++i; i < c.size(); i += i & -i) c[i] += v;
      |                   ~~^~~~~~~~~~
shoes.cpp: In function 'll count_swaps(std::vector<int>)':
shoes.cpp:23:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     for (int i = 0; i < seq.size(); i++) pos[seq[i]] = i;
      |                     ~~^~~~~~~~~~~~

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