Submission #296607

#	Time	Username	Problem	Language	Result	Execution time	Memory
296607		zoooma13	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	450 ms	25976 KiB

shoes

#include "bits/stdc++.h"
#include "shoes.h"
using namespace std;

vector <int> bit;
void upd(int idx){
    for(int i=idx+5; i<bit.size(); i+=(i&-i))
        bit[i] += 1;
}
int ask(int idx){
    int ret = 0;
    for(int i=idx+5; i; i-=(i&-i))
        ret += bit[i];
    return ret;
}
int qry(int l ,int r){
    return r < l? 0 : r-l+1 - ask(r)+ask(l-1);
}

long long count_swaps(vector<int> s) {
    bit.resize((int)s.size() + 13);

    map <int ,vector<int>> mp;
    for(int i=(int)s.size()-1; ~i; i--)
        mp[s[i]].push_back(i);

    long long ans = 0;
    for(int i=0; i<s.size(); i++) if(qry(i ,i)){
        int x = s[i]; mp[x].pop_back();
        int y_idx = mp[-x].back(); mp[-x].pop_back();
        upd(i) ,upd(y_idx);
        ans += qry(i+1 ,y_idx-1)+(x > 0);
    }
    return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'void upd(int)':
shoes.cpp:7:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |     for(int i=idx+5; i<bit.size(); i+=(i&-i))
      |                      ~^~~~~~~~~~~
shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:28:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for(int i=0; i<s.size(); i++) if(qry(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