Problem: 2052A - Adrenaline Rush
Language: java

Solution 1 (runtime: 1983 ms):
import java.util.*;
public class AdrenalinRush{
public static void print(Object print){
    System.out.print(print);
}
public static void println(Object print){
    System.out.println(print);
}
public static void println(){
    System.out.println();
}
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] a = new int[n];
    int[] b = new int[n];
    HashMap<Integer, Integer> map = new HashMap<>();
    HashMap<Integer, Integer> map2 = new HashMap<>();
    ArrayList<int[]> arr = new ArrayList<>();
    int ans=0;
    for(int i=0; i<n; i++){
        a[i]=sc.nextInt();
        map.put(i, a[i]);
        map2.put(i+1, n-i-1);
        b[i]=n-i;
    }
    for(int i=1; i<=n; i++){
        for(int j=i+1; j<=n; j++){
            arr.add(new int[]{j, i});
            // println(j+" "+i);
        }
    }
    ans+=n*(n-1)/2;
    for(int j=n-1; j>=0; j--){
        int tar = map.get(j);
        int curr = map2.get(tar);
        for(int i=curr; i<j; i++){
            ans++;
            // println(b[i+1]+" "+b[i]);
            arr.add(new int[]{b[i+1], b[i]});
            int temp=b[i];
            b[i]=b[i+1];
            b[i+1]=temp;
            map2.put(b[i], i);
            map2.put(b[i+1], i+1);
        }
    }
    println(ans);
    for(int[] i: arr){
        println(i[0]+" "+i[1]);
    }

}
}


Solution 2 (runtime: 1093 ms):

import java.io.*;
import java.util.*;

/**
 * Problem    = cf2052a
 * Date       = Mon Jan 27 23:11:17 PST 2025
 */
public class cf2052a {

  static class Pair {
    int x,y;
    Pair(int x, int y){
      this.x=x;this.y=y;
    }
  }

  public void run() {
    int n = in.nextInt();
    int[] p = new int[n+1];
    for(int i = 1; i <= n; ++i){
      p[i]=in.nextInt();
    }
    Set<Integer> s = new HashSet<>();
    
    var pairs = new LinkedList<Pair>();
    for(int i = 1; i <= n; ++i){
      for(int j = p[i]+1; j <= n; ++j){
        if (!s.contains(j)){
          pairs.add(new Pair(j,p[i]));
        }
      }
      for(int j = n; j > 0; j--){
        if (p[i]==j) continue;
        if (!s.contains(j)){
          pairs.add(new Pair(p[i],j));
        }
      }
      s.add(p[i]);
    }
    out.println(pairs.size());
    for(var pair : pairs)
      out.println(pair.x + " " + pair.y);
  }

  /////////////////////////////////////////////////////////////////////////////////
  static InputStream in(){try{if(file!=null)return new FileInputStream(file+".in");
  return System.in;}catch(Exception e){throw new RuntimeException(e);}}static
  OutputStream out(){try{if(file!=null)return new FileOutputStream(file+".out");
  return System.out;}catch(Exception e){throw new RuntimeException(e);}}IR in=new
  IR(in());PrintWriter out=new PrintWriter(out());void c(){out.close();}static
  class IR{BufferedReader r;StringTokenizer t=null;IR(InputStream s){r=new
  BufferedReader(new InputStreamReader(s),32768);}boolean p(){while(t==null||
  !t.hasMoreTokens()){try{String l=r.readLine();if(l==null)return false;t=new
  StringTokenizer(l);}catch(IOException e){throw new RuntimeException(e);}}return
  true;}boolean hasNext(){return p();}String next(){p();return t.nextToken();}int
  nextInt(){return Integer.parseInt(next());}long nextLong(){return Long.parseLong(
  next());}double nextDouble(){return Double.parseDouble(next());}}public static
  void main(String[]args){cf2052a t=new cf2052a();t.run();t.c();}
  /////////////////////////////////////////////////////////////////////////////////
  static String file;
}