Submission #278340

#	Time	Username	Problem	Language	Result	Execution time	Memory
278340		Kastanda	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	111 ms	20344 KiB

shoes

// M
#include<bits/stdc++.h>
//#include "shoes.h"
using namespace std;
const int N = 100055 * 2;
int M[N], F[N];
vector < int > V[N][2];
inline void Add(int i, int val)
{
        for (i += 5; i < N; i += i & - i)
                F[i] += val;
}
inline int Get(int i)
{
        int rt = 0;
        for (i += 5; i; i -= i & - i)
                rt += F[i];
        return rt;
}
long long count_swaps(vector < int > A)
{
        int n = (int)A.size() / 2;
        for (int i = 0; i < n + n; i ++)
                V[abs(A[i])][A[i] > 0].push_back(i);
        int m = 0;
        for (int i = 1; i <= n; i ++)
        {
                assert(V[i][0].size() == V[i][1].size());
                for (int j = 0; j < (int)V[i][0].size(); j ++)
                        m ++, A[V[i][0][j]] = -m, A[V[i][1][j]] = m;
        }
        long long tot = 0;
        memset(M, -1, sizeof(M));
        for (int i = 0; i < n + n; i ++)
        {
                if (M[abs(A[i])] == -1)
                        Add(i, 1), M[abs(A[i])] = i;
                else
                {
                        if (A[i] < 0)
                                tot ++;
                        Add(M[abs(A[i])], -1);
                        tot += Get(M[abs(A[i])]) * 2LL;
                        tot += Get(N - 10) - Get(M[abs(A[i])]);
                }
        }
        return tot;
}

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