Submission #1190140

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Source Code Expand

#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <cmath>

using namespace std;

int main()
{
    ios_base::sync_with_stdio(0);
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; ++i)
        cin >> a[i];
    map<int, int> pos;
    for (int i = 0; i < n; ++i)
        pos[a[i]] = i;
    sort(a.begin(), a.end());
    int odp = 0;
    for (int i = 0; i < n; ++i)
        if (abs(i - pos[a[i]]) % 2 == 1)
            ++odp;
    cout << odp / 2;
    return 0;
}

Submission Info

Judge Result