Submission #298271

#	Time	Username	Problem	Language	Result	Execution time	Memory
298271		emil_physmath	Arranging Shoes (IOI19_shoes)	C++17	65 / 100	143 ms	22236 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);
}
long long count_swaps(vector<int> a) {
    int n = a.size();
    if (n <= 16)
    {
        llong ans = 0;
        while (true)
        {
            int j = -1;
            for (int i = 0; i < n; i += 2)
                if (abs(a[i]) != abs(a[i + 1]) || a[i] > 0 || a[i + 1] < 0) {
                    j = i;
                    break;
                }
            if (j == -1) break;
            int i = j + 1;
            while (abs(a[i]) != abs(a[j]) || (a[i] < 0) == (a[j] < 0))
                ++i;
            while (i > j + 1) {
                ++ans;
                swap(a[i - 1], a[i]);
                --i;
            }
            if (a[j] > 0) {
                swap(a[j], a[j + 1]);
                ++ans;
            }
        }
        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: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15