Submission #644407

#	Time	Username	Problem	Language	Result	Execution time	Memory
644407		a_aguilo	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	344 ms	75948 KiB

shoes

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

using namespace std;

int N;

void change(int index, int delta, int BIT[]){
    for(; index <N; index += (index&(-index))){
        BIT[index]+=delta;
    }
}

int query(int index, int BIT[]){
    int ans = 0;
    for(; index > 0; index -= (index&(-index))) ans+= BIT[index];
    return ans;
}

long long count_swaps(vector<int> s) {
    map<int, queue<int>> M;
    N = s.size()+1;
    int BIT[N];
    memset(BIT, 0, sizeof(BIT));
    for(int i = 1; i < N; ++i) change(i, 1, BIT);
    long long ans = 0;
    for(int i = 0; i < s.size(); ++i){
        //cout << i << " " << ans << endl;
        if(M.find(-s[i]) == M.end()){
            if(M.find(s[i]) == M.end()){
                M[s[i]] = queue<int>({i});
            }
            else if(M[s[i]].empty()){
                M[s[i]] = queue<int>({i});
            }
            else{
                M[s[i]].push(i);
            }
        }
        else if(M[-s[i]].empty()){
            if(M.find(s[i]) == M.end()){
                M[s[i]] = queue<int>({i});
            }
            else if(M[s[i]].empty()){
                M[s[i]] = queue<int>({i});
            }
            else{
                M[s[i]].push(i);
            }
        }
        else{
            if(s[i] < 0) ans++;
            //cout << "a ";
            int prev = M[-s[i]].front();
            //cout <<"b ";
            M[-s[i]].pop();
            //cout <<"c ";
            ans += (long long)query(i, BIT)-(long long)query(prev+1, BIT);
            //cout <<"d ";
            change(i+1, -1, BIT);
            //cout << "e ";
            change(prev+1, 1, BIT);
        }

    }
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |     for(int i = 0; i < s.size(); ++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