Submission #599862

#	Time	Username	Problem	Language	Result	Execution time	Memory
599862		isaachew	Art Collections (BOI22_art)	C++17	100 / 100	1560 ms	676 KiB

art

#include "art.h"
/*
 Guess permutation from number of inverted (unordered) pairs
 Maximum can be found
 
 Find the minimum element by placing them at the start, then querying
 n(n+1)/2 queries; satisfies ST2
 
 Swap a block to know how many in one are less than the other
 
 O(n log n) sort?
 Score of x 1 2 ... N-2 N-1 N = score of original - sum(a_i>a_x) + sum(a_i<a_x)
 sum(a_i>a_x) + sum(a_i<a_x) = x (quicksort-like comparison)
 (newscore-curscore+x)/2
 
 Already sorted a region; query
 
 2n-2 solution; This gives 70? points
 
 Next score can be computed as score of original - sum(a_i>a_x)
 This has a count of N
 */
void solve(int N) {
    std::vector<int> cperm;
    cperm.push_back(1);
    std::vector<int> curq;
    for(int i=0;i<N;i++){
        curq.push_back(i+1);
    }
    int ns=publish(curq);
    for(int i=1;i<N;i++){
        curq.clear();
        curq.push_back(i+1);
        curq.insert(curq.end(),cperm.begin(),cperm.end());
        for(int j=i+1;j<N;j++){
            curq.push_back(j+1);
        }
        int q2=publish(curq);
        int place=(q2-ns+i)/2;
        ns-=(i-place);
        cperm.insert(cperm.begin()+place,i+1);
    }
    answer(cperm);
}

Compilation message (stderr)

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