Submission #568494

#	Time	Username	Problem	Language	Result	Execution time	Memory
568494		stevancv	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	91 ms	16532 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
using namespace std;
const int N = 1e5 + 2;
const ll mod = 1e9 + 7;
int bit[2 * N];
void Add(int x) {
    for (; x < 2 * N; x += x & (-x)) bit[x]++;
}
int Get(int x) {
    int ans = 0;
    for (; x > 0; x -= x & (-x)) ans += bit[x];
    return ans;
}
long long count_swaps(vector<int> s) {
    int n =  s.size() / 2;
    vector<vector<int>> pa(n), pb(n);
    for (int i = 0; i < 2 * n; i++) {
        if (s[i] > 0) {
            s[i] -= 1;
            pb[s[i]].push_back(i);
        }
        else {
            s[i] += 1;
            pa[abs(s[i])].push_back(i);
        }
    }
    ll ans = 0;
    vector<array<int, 2>> p;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < pa[i].size(); j++) {
            if (pa[i][j] > pb[i][j]) {
                swap(pa[i][j], pb[i][j]);
                ans += 1;
            }
            p.push_back({pa[i][j], pb[i][j]});
        }
    }
    sort(p.begin(), p.end());
    vector<int> all;
    for (int i = 0; i < n; i++) {
        all.push_back(p[i][0]);
        all.push_back(p[i][1]);
    }
    for (int i = all.size() - 1; i >= 0; i--) {
        ans += Get(all[i] + 1);
        Add(all[i] + 1);
    }
    return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:35:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |         for (int j = 0; j < pa[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15