Submission #845216


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#include <iostream>
#include <vector>
#include <cmath>
#include <ctime>
#include <cassert>
#include <cstdio>
#include <queue>
#include <set>
#include <map>
#include <fstream>
#include <cstdlib>
#include <string>
#include <cstring>
#include <algorithm>
#include <numeric>

#define mp make_pair
#define mt make_tuple
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define forn(i, n) for (int i = 0; i < (int)(n); ++i)
#define for1(i, n) for (int i = 1; i <= (int)(n); ++i)
#define ford(i, n) for (int i = (int)(n) - 1; i >= 0; --i)
#define fore(i, a, b) for (int i = (int)(a); i <= (int)(b); ++i)

using namespace std;

typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector<vi> vvi;
typedef long long i64;
typedef vector<i64> vi64;
typedef vector<vi64> vvi64;

template<class T> bool uin(T &a, T b) { return a > b ? (a = b, true) : false; }
template<class T> bool uax(T &a, T b) { return a < b ? (a = b, true) : false; }

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.precision(10);
    cout << fixed;
#ifdef LOCAL_DEFINE
    freopen("input.txt", "rt", stdin);
#endif

    int n;
    cin >> n;
    vi a(n);
    forn(i, n) cin >> a[i];
    vi v = a;
    sort(all(v));
    map<int, int> m;
    forn(i, v.size()) m[v[i]] = i;
//    i64 S = 1LL * n * (n - 1) / 2;
    int ans = 0;
    forn(i, n) {
        int x = m[a[i]];
        ans += (i % 2 != x % 2);
    }
    cout << ans / 2 << '\n';

#ifdef LOCAL_DEFINE
    cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
    return 0;
}

Submission Info

Submission Time
Task C - BBuBBBlesort!
User endagorion
Language C++14 (GCC 5.4.1)
Score 600
Code Size 1732 Byte
Status AC
Exec Time 118 ms
Memory 5760 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 600 / 600
Status
AC × 2
AC × 24
Set Name Test Cases
Sample s1.txt, s2.txt
All 01.txt, 02.txt, 03.txt, 04.txt, 05.txt, 06.txt, 07.txt, 08.txt, 09.txt, 10.txt, 11.txt, 12.txt, 13.txt, 14.txt, 15.txt, 16.txt, 17.txt, 18.txt, 19.txt, 20.txt, 21.txt, 22.txt, s1.txt, s2.txt
Case Name Status Exec Time Memory
01.txt AC 118 ms 5760 KB
02.txt AC 117 ms 5760 KB
03.txt AC 117 ms 5760 KB
04.txt AC 118 ms 5760 KB
05.txt AC 114 ms 5760 KB
06.txt AC 114 ms 5760 KB
07.txt AC 113 ms 5760 KB
08.txt AC 74 ms 5760 KB
09.txt AC 74 ms 5760 KB
10.txt AC 73 ms 5760 KB
11.txt AC 73 ms 5760 KB
12.txt AC 74 ms 5760 KB
13.txt AC 75 ms 5760 KB
14.txt AC 115 ms 5760 KB
15.txt AC 114 ms 5760 KB
16.txt AC 114 ms 5760 KB
17.txt AC 113 ms 5760 KB
18.txt AC 4 ms 256 KB
19.txt AC 4 ms 256 KB
20.txt AC 4 ms 256 KB
21.txt AC 4 ms 256 KB
22.txt AC 4 ms 256 KB
s1.txt AC 4 ms 256 KB
s2.txt AC 4 ms 256 KB