Submission #298283

#	Time	Username	Problem	Language	Result	Execution time	Memory
298283		emil_physmath	Arranging Shoes (IOI19_shoes)	C++17	45 / 100	125 ms	27268 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
using llong = long long;
#define BUGO(x) cerr << #x << " = " << x << '\n';
const int maxN = 200'005;

int t[maxN * 4];

vector<int> chng;
void Add(int v, int vl, int vr, int i, int val) {
    chng.push_back(v);
    if (vl == vr) {
        t[v] = val;
        return;
    }
    int vm = vl + (vr - vl) / 2;
    if (i <= vm)
        Add(v * 2, vl, vm, i, val);
    else
        Add(v * 2 + 1, vm + 1, vr, i, val);
    t[v] = t[v * 2] + t[v * 2 + 1];
}
int Count(int v, int vl, int vr, int l, int r)
{
    if (l > vr || vl > r) return 0;
    if (l <= vl && vr <= r) return t[v];
    int vm = vl + (vr - vl) / 2;
    return Count(v * 2, vl, vm, l, r) + Count(v * 2 + 1, vm + 1, vr, l, r);
}
vector<int> pos_[maxN];
vector<int>* pos = pos_ + maxN;
long long count_swaps(vector<int> a) {
    int n = a.size();
    if (n <= 16)
    {
        for (int i = 0; i < n; ++i)
            pos[a[i]].push_back(i);
        for (int i = -n; i <= n; ++i)
            reverse(pos[i].begin(), pos[i].end());
        llong ans = 0;
        for (int i = 0; i < n; i += 2)
        {
            if (abs(a[i]) == abs(a[i + 1]) && a[i] < 0 && a[i + 1] > 0) {
                pos[a[i]].pop_back();
                pos[a[i + 1]].pop_back();
                continue;
            }
            int j = pos[-a[i]].back();
            pos[-a[i]].pop_back();
            while (j > i + 1) {
                ++ans;
                swap(a[j - 1], a[j]);
                --j;
            }
            if (a[i] > 0) {
                swap(a[i], a[i + 1]);
                ++ans;
            }
            pos[a[i]].pop_back();
        }
        return ans;
    }
    llong ans = 0;
    int l = 0, r = 0;
    vector<int> pos(n);
    for (int i = 0; i < n; ++i)
        if (a[i] < 0)
            pos[i] = l++ * 2;
        else
            pos[i] = r++ * 2 + 1;
    for (int i = 0; i < n; ++i)
    {
        ans += Count(1, 0, n - 1, pos[i], n - 1);
        Add(1, 0, n - 1, pos[i], 1);
    }
    return ans;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15