Submission #312815

#	Time	Username	Problem	Language	Result	Execution time	Memory
312815		Basilhijaz	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	587 ms	548340 KiB

shoes

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

using namespace std;

#define pb push_back

vector<pair<int, int> > pairs;

const int N = 1e6;
long long seg[4*N];
bool done[N];


void build(int p, int s, int e){
    if(s == e){
        seg[p] = 1;
        return;
    }
    build(2*p, s, (s + e)/2);
    build(2*p + 1, (s + e)/2 + 1, e);
    seg[p] = seg[2*p] + seg[2*p + 1];
}

void update(int p, int s, int e, int i){
    if(s == e){
        if(s == i){
            seg[p] = 0;
        }
        return;
    }
    if(i <= (s + e)/2)update(2*p, s, (s + e)/2, i);
    else update(2*p + 1, (s + e)/2 + 1, e, i);
    seg[p] = seg[2*p] + seg[2*p + 1];
}

long long get(int p, int s, int e, int a, int b){
    if(a <= s && b >= e){
        return seg[p];
    }
    else if(b < s || a > e){
        return 0;
    }
    return get(2 * p, s, (s + e)/2, a, b) + get(2 * p + 1, (s + e)/2 + 1, e, a, b);
}
long long count_swaps(vector<int> s) {
    int n = s.size();
    queue<int> left[2*n + 1];
    queue<int> right[2*n + 1];
    for(int i = 0; i < n; i++){
        if(s[i] < 0){
            if(!right[abs(s[i])].empty()){
                pairs.pb({right[abs(s[i])].front(), i});
                right[abs(s[i])].pop();
            }
            else{
                left[abs(s[i])].push(i);
            }
        }
        else{
            if(!left[s[i]].empty()){
                pairs.pb({left[s[i]].front(), i});
                left[s[i]].pop();
            }
            else{
                right[s[i]].push(i);
            }
        }
    }
    build(1, 0, n - 1);
    long long ans = 0;
    sort(pairs.begin(), pairs.end());
    for(int i = 0; i < pairs.size(); i++){
        if(s[pairs[i].first] > 0){
            ans++;
        }
    }
    memset(done, 0, sizeof(done));
    for(int i = 0; i < pairs.size(); i++){
        update(1, 0, n - 1, pairs[i].second);
        ans += get(1, 0, n - 1, pairs[i].first + 1, pairs[i].second - 1);
    }
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:73:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |     for(int i = 0; i < pairs.size(); i++){
      |                    ~~^~~~~~~~~~~~~~
shoes.cpp:79:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |     for(int i = 0; i < pairs.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