Submission #604319

#	Time	Username	Problem	Language	Result	Execution time	Memory
604319		Jomnoi	Art Collections (BOI22_art)	C++17	100 / 100	1700 ms	672 KiB

art

#include <bits/stdc++.h>
#include "art.h"
using namespace std;

//
// --- Sample implementation for the task art ---
//
// To compile this program with the sample grader, place:
//     art.h art_sample.cpp sample_grader.cpp
// in a single folder, then open the terminal in this directory (right-click onto an empty spot in the directory,
// left click on "Open in terminal") and enter e.g.:
//     g++ -std=c++17 art_sample.cpp sample_grader.cpp
// in this folder. This will create a file a.out in the current directory which you can execute from the terminal
// as ./a.out
// See task statement or sample_grader.cpp for the input specification
//

const int MAX_N = 1e4 + 5;

int fenwick[MAX_N], position[MAX_N];

void add(int x, int v) {
    for(int i = x; i < MAX_N; i += (i & -i)) {
        fenwick[i] += v;
    }
}

int get(int x) {
    int res = 0;
    for(int i = x; i >= 1; i -= (i & -i)) {
        res += fenwick[i];
    }
    return res;
}

void solve(int N) {
    int inversion, new_inversion, between, l, r, mid, pos;
    vector <int> order(N);

    for(int i = 1; i < MAX_N; i++) {
        fenwick[i] = i & -i;
    }

    iota(order.begin(), order.end(), 1);
    inversion = publish(order);

    position[1] = MAX_N / 2;
    add(MAX_N / 2, -1);
    for(int i = N - 1; i >= 1; i--) {
        swap(order[0], order[i]);
        new_inversion = publish(order);

        between = (abs(new_inversion - inversion) - 1) / 2 + 1;
        if(inversion > new_inversion) {
            l = 1, r = position[order[i]] - 1;
            while(l <= r) {
                mid = (l + r) / 2;

                if(get(position[order[i]] - 1) - get(mid - 1) >= between) {
                    l = mid + 1;
                    pos = mid;
                }
                else {
                    r = mid - 1;
                }
            }
        }
        else {
            l = position[order[i]] + 1, r = MAX_N - 1;
            while(l <= r) {
                mid = (l + r) / 2;

                if(get(mid) - get(position[order[i]]) >= between) {
                    pos = mid;
                    r = mid - 1;
                }
                else {
                    l = mid + 1;
                }
            }
        }

        position[order[0]] = pos;
        add(pos, -1);
        inversion = new_inversion;
    }

    int min_value = MAX_N;
    for(int i = 1; i <= N; i++) {
        min_value = min(min_value, position[i]);
    }
    for(int i = 1; i <= N; i++) {
        position[i] -= min_value;
    }

    vector <int> ans(N);
    for(int i = 1; i <= N; i++) {
        ans[position[i]] = i;
    }
    answer(ans);
}

Compilation message (stderr)

art.cpp: In function 'void solve(int)':
art.cpp:83:28: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   83 |         position[order[0]] = pos;
      |         ~~~~~~~~~~~~~~~~~~~^~~~~
interface.cpp: In function 'int publish(std::vector<int>)':
interface.cpp:20:17: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   20 |     if(v.size() != N) {
      |        ~~~~~~~~~^~~~
interface.cpp: In function 'void answer(std::vector<int>)':
interface.cpp:36:17: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   36 |     if(v.size() != N) {
      |        ~~~~~~~~~^~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30