Submission #875185

#	Time	Username	Problem	Language	Result	Execution time	Memory
875185		StefanL2005	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	92 ms	18904 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
#define ll long long

void update(int node, int left, int right, int point, vector<int> &tree)
{
    if (left == right)
        tree[node] = 1;
    else
    {
        int m = (left + right) / 2;
 
        if (point <= m)
            update(2*node, left, m, point, tree);
        else
            update(2*node + 1, m + 1, right, point , tree);
    
        tree[node] = tree[2*node] + tree[2*node + 1];
    }
}
 
int querry(int node, int l, int r, int ql, int qr, vector<int> &tree)
{
    if (ql <= l && r <= qr)
        return tree[node];
    
    int m = (l + r) / 2;
 
    if (qr <= m)
        return querry(2 * node, l, m, ql, qr, tree);
    if (ql > m)
        return querry(2 * node + 1, m + 1, r, ql, qr, tree);
    
    return querry(2 * node, l, m, ql, qr, tree) + querry(2 * node + 1, m + 1, r, ql, qr, tree);
}

ll count_swaps (vector<int> S)
{
    int n = S.size() / 2;
    ll ans = 0;
    vector<int> Taken(2 * n, 0);
    vector<int> Tree(8 * n, 0);
    vector<vector<int>> Poz(2 * n + 1);
    vector<int> l(2*n + 1, 0);

    for (int i = 0; i < 2 * n; i++)
    {
        if (S[i] < 0)
            Poz[abs(S[i])].push_back(i);
        else
            Poz[S[i] + n].push_back(i);
    }
    
    for (int i = 0; i < 2 * n; i++)
    {
        if (Taken[i] == 1)
            continue;

        int p1 = Poz[abs(S[i])][l[abs(S[i])]];
        int p2 = Poz[abs(S[i]) + n][l[abs(S[i]) + n]];

        l[abs(S[i])]++;
        l[abs(S[i]) + n]++;
        Taken[p1] = 1; Taken[p2] = 1;

        if (p2 == p1 + 1)
            continue;
            
        if (p1 < p2)
            ans += p2 - p1 - 1 - querry(1, 0, 2*n-1, p1, p2, Tree);
        else    
            ans += p1 - p2 - querry(1, 0, 2*n-1, p2, p1, Tree);

        update(1, 0, 2*n-1, p1, Tree);
        update(1, 0, 2*n-1, p2, Tree);
        Taken[p1] = 1; Taken[p2] = 1;
    }
    return ans;
}

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