Järjestys

#include <bits/stdc++.h>
 
#define uint unsigned int
#define ull unsigned long long
#define INF 1000000001
#define LINF 1000000000000000001
#define ll long long
#define ld long double
#define M 1000000007
#define E 0.0000001
#define N (1<<17)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pdd pair<double, double>
#define pld pair<long double, long double>
#define cll complex<long long>
#define cld complex<long double>
#define X real()
#define Y imag()
#define C 'a'
#define F first
#define S second
#define PI 3.1415926535897932384626433
 
using namespace std;
 
int v[2*N];
 
void inc (int k) {
    k += N;
    v[k]++;
    for (k /= 2; k >= 1; k /= 2) v[k] = v[2 * k] + v[2 * k + 1];
}
 
int sum (int k) {
    int a = 1;
    int b = k;
    a += N;
    b += N;
    int s = 0;
    while (a <= b) {
        if (a % 2 == 1) s += v[a++];
        if (b % 2 == 0) s += v[b--];
        a /= 2; b /= 2;
    }
    return s;
}
 
int p[N];
 
int main () {
    int n;
    cin>>n;
    for (int i = 1; i <= n; i++) {
        int x;
        cin>>x;
        p[x] = i;
    }
    vector<int> ans;
    for (int i = n; i > 1; i--) {
        int x = p[i] - sum(p[i]);
        //cout<<i<<" -> "<<x<<endl;
        inc(p[i]);
        if (x != 1) ans.push_back(x - 1);
        if (x != 1) ans.push_back(x);
        ans.push_back(i);
        ans.push_back(i - 1);
    }
    cout<<ans.size()<<endl;
    for (int i : ans) cout<<i<<" ";
    cout<<endl;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED